Кольцо стопорное.

R200W-3, R200W-7, R200W-7A, R210W-9, R210W-9MH, R210W-9S, R450LC-3, R450LC-7, R450LC-7A, R480LC-9, R480LC-9MH, R480LC-9S, R500LC-7, R500LC-7A, R520LC-9