Original Campagnolo replacement cassette lockrings. **There are four types:*** 9/10 speed compatible (all 9/10 speed cassettes from 2000 onwards plus Record & Chorus cassettes from 1999)* 11 speed compatible (all 11 speed cassettes from 2009 onwards)* 12 speed compatible (all 12 speed cassettes from 2019 onwards)* 13 speed compatible (all 13 speed cassettes from 2020 onwards)**Please also check what tooth your first sprocket is:*** Select 11T - for 11 tooth first sprocket* Select 12T - for 12 or 13 tooth first sprocket**FEATURES:*** Original Campagnolo Spare part**CAMPAGNOLO PART NUMBER*** CS-501 (9/10x, 11T)* CS-401 (CPS45 9/10x, 12T)* CS-111 ( 11x, 11T)* CS-112 (11x, 12T)* CS-511 (12x)* AC21-N3W (13x 11T)