The Sync was designed for use on push carts. We started with a top and bottom built to nest in the upper and lower bag wraps of Sun Mountain carts. Then we molded the bottom so it fits over the lower bag rest of the Speed Cart and Micro-Cart Series carts, minimizing side-to-side movement.
Disclaimer: The earliest version of our Speed Cart, the Pre-V1, had a rounded bag support. This rounded bag support does not fit with the Sync cart bag.