Note for U.S. Customers
This item can be purchased from our trusted partners at Eagle Bear | Prevelo (based in California) order directly here: 

Mac-Ride Adapters and Parts – Eaglebear

This is a Ride More front mount spacer for a 1 ¹/⁴" threadless steerer tube - Giant Overdrive 2. This is only found on Giant bikes from 2011-2014.

Check your headset - if it's 1¹/⁴" it should say "Overdrive 2".