Disco A$s Blazer (coat): +1 Espirit de Corps

White Satin Shirt: +1 Conceptualization, -1 Suggestion

Flare-cut Trousers: +1 Electrochemistry, -1 Savoir Faire

Horrific Necktie: +1 Inland Empire. Requires Savoir Faire check to grab from the fan, lower difficulty if you turn the fan off.
(Note - you should wear this while talking to the drunks and right after confronting the instigator. If your Inland Empire is high enough, you should get additional options).

Green Snakeskin Shoes: +1 Composure, -1 Savoir Faire. One is in your room, another is on the balcony outside (head straight down from your room to open the door to the balcony).

Yellow Gardening Gloves: +1 to Interfacing (require Interfacing or Inland Empire check). Talk to the gardener right outside the hotel (Day 1). Alternately, tell the gardener you handled a dead body once she moves inside the hotel on day 2+. (Thanks to artmangm).

White Tank Top: +1 Physical Instrument. South-east of King Filippe’s statue in the lorry jam.

D1ck Mulen’s Hat: +1 Encyclopedia. From Annette the book store girl, after you convince her mother to let her in.
Note: If you give this hat away, Annette will give you an identical one if you talk to her again.

Orange Bum Hat: +1 Reaction Speed, -1 Rhetoric. Next to the “Weasel"’s door, north of the lot where the hanged body is.

Signal Blue Navy Coat: +1 to Suggestion, -1 Half-Light. Right below where Cindy the Skull hangs out, in the north-west section of the town. You need to equip a tool to open the container.

Fingerless Gloves: +1 Electrochemistry. Garbage container outside pawn shop.

Neat Office Shades: +1 Visual Calculus, -1 Drama. The bathroom of the office at the entry to the harbor.

RCM Patrol Cloak: +1 Espirit de Corps, +1 Shivers. At the entrance to the harbor area. If you reach the area above the harbor through Cuno’s shack, passing a Savoir Faire check to jump down and reach the cloak is your only way to actually enter the harbor (that is, the option is gone once the cloak is no longer there).

FALN gloves: +1 Half-Light. Next to Evrart’s container in the harbor area.

The simplest way to enter the apartment building is to talk to the smoking man on the balcony, behind the hanged-man lot.

Flip-up Glasses “The Auditor”: +1 Logic, -1 Authority. Right across from the backdoor entrance to the building.

Saramirizian Lounge Jacket: +1 Conceptualization. Communist student’s apartment. Requires an interface check and a pair of chaincutters to break in.

Black Monkstraps (shoes): +1 to Indirect Modes of Taxation. Apartment 10 in the apartment building. Requires talking to the cleaning lady and getting the quest to check the apartment out.
Note: "+1 to [thought]" clothing helps trigger the thought quicker. As though you've selected one more thought-triggering dialog option than you really had.

Pour L’Homme Laborer Jeans: +1 Electrochemistry, -1 Reaction Speed. Cindy’s coal room in the Apartment Building.
(Put these on to discover an apricot flavored gum wrap).

Regular Black Jeans: +1 Composure. Cuno's apartment - pass the empathy check and agree to break in.

Samaran Conical Hat: +1 Logic, -1 Suggestion. Smoking man’s apartment. Ask the cleaning lady about where he lives and come to his apartment after 21:00 the next day.

Party Dragon’s Silk Robe: +1 Drama, +1 Electrochemistry. Smoking man’s apartment.

"Frittte" Plastic Rain Coat: +1 Endurance. Bought at the Frittte shop, for 4 réal (counter to the right of the radio). Can be stolen with a Savoir Faire check.

Man from Hjelmdall T-shirt: +1 Shivers, +1 Physical Instrument, -2 Authority. Pawn shop, next to the street light. 2 réal, or a number of dialog options with no stat checks to get it for free.

FALN modular track pants: +1 Savoir Faire, +1 Physical Instrument. 15 réal from Cuno after passing the big empathy check, provided he offered to sell you the pants beforehand (ask about the crime scene and the dead man's clothes).

Shades of Self-Destruction: +1 Electrochemistry, -1 Logic. Bought from Siileng for 2.5 réal.

Sunglasses “Subinsulindic Rendezvous”: +1 Inland Empire, -1 Perception. Bought from Siileng for 3 réal, after passing a Conceptualization check.

Dynamic Windbreaker “Surf”: +1 Composure, -1 Shivers, Bought from Siileng for 4.5 réal, after passing a Composure check.

FALN “Ultra Series” sneakers: +1 Reaction Speed, +1 Hand/Eye Coordination, -1 Encyclopedia. Bought from Siileng for 50 réal, after passing a Conceptualization check. Come with an 0.5 réal pair of speakers that can be sold for 5 réal.

"Amphibian" sports visor: +1 Perception. Bought from Siileng for 6 réal, after *failing* a Conceptualization check as you try to find better sunglasses.

Itchy Pants: +2 Half-Light, -1 Composure, -1 Savoir Faire. Bought from Siileng for 2 réal after failing a composure check when rummaging through his bin.

Insane Mesh Top: +1 Drama. Basement of the Doomed Commercial Area, right next to the exit that leads to the hotel doors.

Interisolary Dress Shirt: +1 Logic. Behind the door Everat asks you to open.

Pinball Maker’s Coat: +1 Empathy, +1 Hand/Eye Coordination. Locked section of the hotel, behind the blue door.

Medal “The Setting Sun”: +1 Rhetoric. From Rene, the old petanque playing soldier. Pass a Composure check, hear out his war story, then pass Rhetoric skill check and ask for the medal.

Jamrock Biker-Cop Sunnies: +1 Empathy, -1 Logic. Just past the canal, next to the raised bridge. Container requires a tool (prybar or chaincutters) to open.

Bow Knot: +2 Drama. Abandoned shack to the south-east of the fishing village.

Interisolary Trousers: +1 to the Kingdom of Conscience. House in fishing village with “Allez Vous-En” on the roof, north-east of the drunks.

Franconigerian Cavalry Boots: +1 to Perception. Right next to Lilienne on the fishing village peer.

Korojev Jacket: +1 to Logic. Inside your room in the Fishing Village

White Polo Shirt: +1 Rhetoric, -1 Empathy. South of the radio tower, directly east of the closed bunker door.

Scented Scarf: +1 Shivers, -2 Physical Instrument. Next to the radio tower on the northern end of the coastline.

FALN “Faln” Winbreaker: +1 Pain Threshold, +1 Half-Light, -1 Drama: Find the sh1t-covered jacket on the boardwalk. Isobel in the fishing village can wash it (takes half an hour).

Mega-Bino’s Prescription Glasses: +2 to Encyclopedia, -1 Perception. On the boardwalk, north of the Filthy Jacket.

Oversized Superstar Glasses: +1 Savoir Faire, -1 Visual Calculus. South of the cryptozoologists.

FALN “Pipo” Pipo: +2 Logic, -1 Perception. North-east of the execution wall, south of the boardwalk.

Speedfreaks DONKS: +1 Physical Instrument, +1 Electrochemistry, -1 Interfacing.

Complicated and involves spoilers:

Fail the Shivers check at the FELD Building TWICE. You will be directed to talk to the twins (Lilian's children). Talk to them, the washerwoman, and head to Kim's car. Make sure your Reaction Speed is at least 6, and you'll be able to ask for Speedfreaks merch, which should arrive the next day.

Reflective Construction Vest: +1 Endurance, -1 Reaction Speed. Communist reading group, if you undergo the communist vision quest.

Mesque Banger’s Silk Scarf: +1 Pain Threshold. Inside the church.

Mesque Banger’s Red Brogues: +1 Empathy. Inside the church.

Specialist-Grade Headset: +2 Inland Empire, -1 Reaction Speed. Complete the moralist vision quest without getting picked up by the airship.

Eight-Eyed Teratorn Tie: +1 Inland Empire, +1 Volition. Lena, the cryptozoologist’s wife, will give this to you after you convince her husband to come back.

Leather Jacket “Pissf****t”: +1 Drama, -1 Authority
Leather Jacket “F*ck the World”: +1 Half-Light, -1 Rhetoric
Talk to the wannabe Skulls next to Kim’s car on day 4. Intimidate them repeatedly to get an easy Half-Light check to get both jackets. Failing the check will only get you the jacket you wanted Kim to wear.

RCM Lieutenant’s Hat: +1 Authority. Get it from “the Pigs” after the confrontation.

Interisolary Suit Jacket: +1 Suggestion. Basement of the Field Electric building.

Revolutionary’s Hat: +1 to Mazovian Socio-Economics. Basement of the Field Electric building, room revealed with flashlight.

Polar Anorak: +1 Composure, +1 Shivers. Caverns section of Field Electric building basement.

Royal Carabineer Jacket: +1 to Revacholian Nationhood. Found in Rene’s booth in the harbor on day 5.

Royal Carabineer Pants: +1 to Reaction Speed . Found in Rene’s booth in the harbor on day 5.

FALN “Arrower” Shirt: +1 Hand/Eye Coordination. On the islet, inside the flak tower.

Army Surplus Winter Scarf: +2 Empathy, -1 Composure. On the islet, inside the flak tower.

In order to get the quest to obtain the T-500 armor parts, you need to inspect the hanged man's body and check the boots. When asked whether you intend to steal the boots, reply affirmatively (you can say that doing so would be dishonorable to gain an honor point, then repeat the dialog action to undertake the quest). Talk to Cuno and Manana about the armor, saying you intend to get all of it. Talk to Cindy the Skull about the gauntlets.

(Actually, declaring that you intend to get all the armor parts allows you to steal the boots regardless of what you decide to do when you first examine them)

Fairweather T-500 Greaves: +2 Authority, -1 Composure. Having previously affirmed that you intend to steal the boots, complete the autopsy and part with Kim without sending the body to processing (going to your room in the evening is the simplest way to do so). Then, instead of going to sleep, come back, steal the boots, and clean them in the hotel kitchen.

Fairweather T-500 Gauntlets: +2 to Interfacing. Talk to Cindy the Skull, then little girl inside the fishing village house (next to the twins). Check the sandcastle behind the house.

Fairweather T-500 Cuirass: +1 Pain Threshold, +1 Volition, -1 Empathy. Gary the Crypto-Fascist. Recover the mug from the dumpster, then talk to him and pass a Composure check.
Note - Gary WILL eventually go home and be inaccessible if you proceed with the cryptozoologist quest.

Fairweather T-500 Helmet: +1 Half-Light, -1 Suggestion. Gained during the very endgame, on the edge of the island, after the interrogation.

Other guides I wrote for this game include:

Thought Cabinet guide

How to be Kim's best friend

All XP and $$$ from bonus thoughts

Let me know if I got anything wrong or omitted relevant info.

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