Can you ever have too many bikes? Nope. 

That's why some of you might like extra spacers, so you can pre-install your Mac Ride front mount spacer on as many bikes as you like and swap your Mac Ride seat hassle-free! The front mount spacer weighs only 9g!

1-1/8" is the most common size - check your bike if you are unsure!

The spacer is a small, light weight ring that replaces existing spacer(s) on your bike's steerer tube.

Every Mac Ride seat purchased comes with two such spacers - one already snug in the seat's front mounting bracket, and a spare in your box.