RD-M55  Long cage for 9 speed, total capacity 45 T, max. rear sprocket 34 T.

RD-M55S Short cage for 9 speed, total capacity 39T, max. rear sprocket 34 T.

weight : 229g

RD-M45 Long cage for 8/9 speed ,total capacity 45T, max. rear sporcket 34T .

RD-M45S Short cage for 8/9 speed , total capacity   39T , max. rear sporcket 34T

RD-M35 Long cage for 7/8 speed ,total capacity 45T,max. rear sprocket 34T .

RD-M35S Short cage for 7 / 8 speed , total capacity 39T , max. rear sprocket 34T .