SunSmart Pro DSLR 15mm rod support system Follow Focus With 2 stoppers and Gear Ring Belt for DSLR cameras Present the most innovative and needed function-Movable Focus Indicator. Easy begin/end setup for accurate and highly repeatable racking between your desired indicator location with 2 stoppers. Completely gear-driven design for slip-free, accurate, and repeatable focus movement. 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). Suitable for adjustable mount lens from 52mm-86mm. Compatible with all DSLR cameras, video cameras. Make of high grade aluminum construction. With adjustable flexible gear belt.