Ball Bearing Mechanism 17", and 22"

Refers to the under-desk mounted track that the mechanism slides along. Measure the amount of flat space you have on the under-side (from front to back of your desk) to determine which track length best suits you. The longer the track you are able to fit, the farther underneath the desk you will be able to slide the platform. The track measures 5-1/2" in width and is available in seven lengths.