Follow Focus Finder F3 for 15mm Rod Support DSLR (F3 With Two Hard Stops) Gear drive can be mounted from either side (works for both right-handed and left-handed) Mounts onto 15mm/0.59'' Rod Support (60mm/2.4'' center to center difference). Completely gear-driven design for slip-free, accurate, and repeatable focus movement. Suitable for adjustable mount lens from 52mm-86mm. Compatible with all DSLR cameras, video cameras.