The Mongoose M-3.6.1 builds on our popular M-3.5 with a number of significant refinements: 1) an added dead bolt style lock to both axis for those occasions where you want to carry a mounted lens over your shoulder, change a tele-extender, or remove the Mongoose from the tripod; 2) the tension control is now for tension control only to increase pad life; 3) a stainless steel tension screw for increased strength; a four lobe knob for easy grip and compatibility with the low mount; 5) a slightly smaller form for easier packing. Extremely smooth and fast action with all telephoto lenses including the really big lenses like the Canon EF 800mm f/5.6L IS USM, 600mm f/4.0, 500mm f/4.0, and smaller. Full gimbal action with easy to reach tension and lock controls, adjustable CAM action quick release fits ALL popular ARCA style plates. A light weight sleek shape makes it easy to pack or carry, even in a large pocket. Weight: 1 lbs. 8 ounces. Packing dimensions: Upper arm L; 7.6"; Lower arm L 5.3"; Depth 2.75" at widest point (knob); Profile, 1.8" at thickest point.