When you need accurate repeatability with lighter loads and when trim height is
a problem then the I Beam Belt Drive System is the answer.

The notched belt provides far greater accuracy and reliability
of a compound move in a friction drive system. It contributes to a smooth
and quiet operation, while eliminating the need for traveling cable feeds.
The use of a belt drive eliminates the “slip or progressive creeping”
sometimes associated with a friction drive system. Perfect for
camera systems, light scenic loads, and individual lights.