Piston circlip / snap ring. Most commonly used for (but not limited to) 250cc ATVs such as the Jianshe JS250 Mountain Lion and Baja Wilderness Trail 250 (WD250-U) ATV as well as many other clones, rebrands and similar displacement machines.
Common Jianshe model name is primarily listed as "Jianshe JS250ATV", "Jianshe 250cc ATV" and "Jianshe 250cc Mountain Lion". Common listed Jianshe JS250 circlip / snap ring part number is FG-200701-0 and listed as "Criclip" in their parts lists. Also applies to some variations of Jianshe 250cc Go karts, buggies, UTVs and other products.
Manufacturer Part Number:
FG-200701-0