Fotga DP3000 Offset Raiser Z-shape Railblock Clamp Mount Bracket for 15mm Standard Rail Rod Camera Rig Set Shoulder Rigs The FOTGA DP3000 Z-Shape clamp is for rod support rail system, follow focus support Fits standard 15mm rods, with L M5 screw Blue Knob, strong, simple, great price,anodized black finish It is used to extend left and right rod rail system support,it can extend application of rod support rail system,attach matte box, hand grip, shoulder balance, USB follow focus,follow focus,magic arm, LED light, flash, LCD monitor...If you have more gears, the 4 rods clamp is helpful It is more often used to mount LCD monitor or LED light Material: Anodized aluminum