Spare Part for Garmin Varia RCT715 Seat Post Model:For Pinarello Dogma F/F9/F7/F5, Dogma X, X9/X7/X5, Crossista F, Nytro E Road The only compatible solution is

The only compatible solution is a saddle rail mount

Specifications (Standard):

40mm behind the rear of the saddle

You can identify which version of saddle you have by checking how far back the first mounting point is relevant to the rear of the saddle:

Spare Part for Garmin Varia RCT715 Seat Post Model:For Pinarello Dogma F/F9/F7/F5, Dogma X, X9/X7/X5, Crossista F, Nytro E Road The only compatible solution isHave you purchased a complete seat post mount or race number holder from us? Would you like to exchange the mount to another design, while continuing to use the same seat clamp? No problem! You can now purchase these components separately :) Simply select your bicycle seat post model and we'll do the rest. Please Note: This item is for the light mount only. The seat post clamp is not included.