Locking ring Piston Type B 10X0.8 - 7374410-00 Spare part for chainsaw/brush cutter from the Husqvarna spare parts catalogSuitable for example: Husqvarna 545 Husqvarna 555 Husqvarna 550XP /G/Triobrake Husqvarna 560XP/G Husqvarna 562 XPG Husqvarna T540XP