Soap injector kit fits most pump which is an . Replaces pump 203640GS 308452002, 190593GS and 190635GS. Soap injector makes cleaning so much easier and faster. It's a great replacement for the old rusted one. The brass fitting is a 1/8 inch 27 male thread. Install them and the soap dispenser works just like new. How to install: Take the brass fitting, drop in the little ball, insert spring with small end against the ball, then attach it back on the pump. Do not over-tighten otherwise it snap off. Attention: When you insert injector into receptacle of pump and tighten injector with 13mm wrench, don't overtighten, you'll break the o ring or crack white metal on pump. Compatible: injector kit is compatible with Pump 190593GS, 190635GS and 203640GS. Please check the part number of your pressure washer pump and make sure the soap injector matches your pump. Function: If the part on your pressure washer pump is worn-out, rusted or hard-water-deposit clogged, you can replace it with this