This review is for a 15mm SMALLRIG Rail Clip with 1/4"-20 thread. Rail Rod Support System High-Rise DSLR- CAMVATE aluminum alloy mount base plate and camera grip This is part of a custom extended grip system for use with my Tamron 150-600mm G2 telephoto lens The function was to control the 7.5lb lens and camera system during handheld shooting and to support.The 15mm SMALLRIG Rod Clamp is well made and easily snaps onto the 60mm 15mm bars of the Neewer High Riser Block System.Thanks to the many threaded holes in the SMALLRIG, the 15mm Rail Block Rod Clamp allows for mounting the handle in its normal vertical working position or mounting it horizontally between 15mm rails for storage or transport.