Fotasy FF2B Pro Grade 15mm Rod Rig Follow Focus for HDSLRs and Camcorders, Quick Release, A/B Stop, Tension Screw (Blue/Black) This is a Pro Grade Follow Focus with a variable lock system and a base that slides to accommodate different lens constructions The Follow Focus quickly and securely mounts 15mm rods via a tightening mechanism controlled by a underside knob The variable lock system allows start and end points to be set, and a focus scale helps in measuring distances Full Metal Design, Quick Release, A/B Stop, Tension Screw Fotasy is a registered trade mark