Wossner is Germany's finest aftermarket forged piston and rod manufacturer and have over 25 years of experience in the high-performance racing industry. Top European racers and FIM World Champions rely on Wossner for only the best pistons, rods and customer service.Features In-house designed and manufactured; all forgings are produced in Wossner's company-owned forging operation 4-stroke pistons are made using a double-bridged forging design Lightweight pistons with the tightest piston-wall clearances in the industry give you a quieter running engine All pistons include piston, ring, wrist pin and pin locks Wossner pistons are used by leading Supercross, Arenacross and MX GP teams Made in Germany Specifications Piston Size: 70.94mm Oversize: Standard Number of Rings: 3 Fits: Yamaha YFB250 TIMBERWOLF 2WD 1992-1998 YFB250FW TIMBERWOLF 4WD 1994 1996-2000 YFM250 BEAR TRACKER 2000-2002 2004 YFM250 BIG BEAR (SEMI AUTO) 4WD 2007-2009 YFM250B BRUIN 2X4 2005-2006