1. 21-Teeth Splined Screwdriver For Poulan Weed Eater STIHL ECHO Husqvarna Splined Screw Carburetor. Compatible with manufacturer part number # 530035560. 2. Notice: the carb repair tool is designed to adjust ZAMA carburetors, it won't fit WALBRO carburetors which may need a 22-teeth tool. And does not fit lawnmowers. 3. Used on most two-cycle / stroke engines; Fits many brands of equipment, including Sears, Craftsman, Poulan, Husqvarna, Weedeater, Echo, Toro, Ryobi, Homelite, and anything else that utilizes the splined adjustment screws. Carb Tuning Tool is for Certified Technicians to tune carburetors, and keep engines within EPA specs. 21 spline screwdriver replacement for harbor freight.