The FF-4 has been the standard follow focus for many years.
ARRI UDM-1 Ultrasonic Distance Measure System. The UDM-1 measures the distance from camera film/sensor plane to objects being shot.
The LMB-25 Matte Box is a clamp-on matte box that holds 4x5.65 filters and can be configured with 2 or 3 filter stages.
The Chrosziel 206-01S is a lightweight, single-sided follow focus unit that mounts on 15mm Lightweight Rods.
The MB-18 Studio Matte Box is a rod based matte box that holds 4x5.65 filters and can be configured with 3 or 4 filter stages.