Fangrui Product Details Material: Aluminum Model: Nnr-140 Screw Thread: Unc 1/4-20 Size: Approx. 17 X 3.7 X 1.4cm/ 6.69 X 1.46 X 0.55 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 Corrosion 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: 1 X 140mm Nodal Slide Rail Quick Release Plate Note: Light Shooting 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.