Green’s Dictionary of Slang

(US/N.Z. drugs, also fit and brace) the equipment (a needle, a spoon, a dropper) required for injecting narcotics.

1958		J. Webb Badge (2006) 303: FIT Narcotics — Hypodermic needle, syringe, etc.
1960		C. Cooper Jr Scene (1996) 289: I’m waiting for you to finish cleanin your fit [...] so I can use mine.
1971		E.E. Landy Underground Dict. (1972).
1982		G. Newbold Big Huey 13: I bought five more cans of morphine, and he threw in a fit as well so I could hit myself.
1997		A. Highcrest At Home on the Stroll 186: The offer of needles (‘fits’) made some women uncomfortable.
1999		Crown Public Health 33: Use a new fit every time ... Return used fits to a Needle Exchange for destruction.
2000		Other Side of the Wall: Prisoner’s Dict. July 🌐 Fit: Short for ‘outfit’ — a home-made contrivance for injecting drugs intravenously.
2000		P. Temple Dead Point (2008) [ebook] ‘So Robbie went into his garage [...] shot up. that’s it?’ He nodded. ‘The fit’s there?’ A nod. ‘Tracks?’ ‘Yeah. User’.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 69/2: fit n. a hypodermic syringe [...] fit and brace n. a hypodermic syringe and needle.
2012		L. Redhead ‘Grassed’ in Crime Factory: Hard Labour [ebook] Me and Ron would never leave a fit in someone’s house.