Bikemonger says .... if you have two bikes and want to use your Spinelock on both, this wee gadget on the second bike enables a swift and painless switch.

Revelate says... the seat rail mounted component of the Spinelock stability system. Sold individually as a spare or replacement. Having a second can be handy if you use your Spinelock seat bag on multiple seats or bikes. 

A Torx-25 wrench is needed for installation. You likely already have one on your multi-tool!

Watch this installation guide