SmallRig 15mm Rod Support for 2660 Matte Box 3411is designed to fix Matte Box 2660 (with Silicone Donut 3409, if needed) to a 15mm rail support system. It connects to the bottom threaded hole of Matte Box 2660 via a 1/4''-20 screw, is secure and stable, and features a half-opened rod clamp to be quickly mounted onto the rail support system without disassembling other accessories. The tool-less rod support adopts a thumb screw and knob, which can be adjusted 20.5mm vertically to allow an 80-100.5mm distance between the dual rod center and lens center.