Material: Aluminum Model: NNR-140 Screw Thread: UNC 1/4 inch-20 Size: . 17 x 3.7 x 1.4cm/ 6.69 x 1.46 x 0.55 inch Jaw can be opened from 40mm to 45mm It is widely used with fish-eye-lenses and wide-angle lenses Safety stop relief grooves for protecting your camera from accidental drops Machined from light weight aircraft-grade aluminum, sealing it against and abrasion, has two safety stop screw on back of plate Standard dual dovetail design, with high contrast built-in bubble level to improve alignment Scale on both sides of the rail to adjust the nodal point conveniently and accurately Clamp with screw-knob help you locking equipment quickly Accurately find nodal point for panoramic photography Designed with 8pcs UNC1/4 screw thread for extended function Package Included: 2 x 140mm Nodal Slide Rail Quick Release Plate Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.