"1.Locking System is located on the side of the ball instead of the bottom of the ballhead. Whole center of gravity is lowered more than 15%. 2.Adopts geared locking structure, higher locking strength. 3.360° panning movement with calibrated precision, precisely capture overlapping panoramic images. 4.Compatible with Really right stuff (RRS), Wimberley, Jobu Design, Arca Swiss, Kirk Enterprises, Markins, Photo Clam etc. 5.Ideal for Gitzo, Manfrotto, Sirui, Benro, RRS tripod. SUNWAYFOTO XB Series Superior Low-Profile Ball Head XB-28 With a Standard Screw-Knob Clamp. 6.Main Lock Knob features ratchet mechanism, can be pulled out and relocated at any position desired. 7. 3/8"" mounting hole at the bottom equipped with 1/4"" bushing. Product details： Superior Low-Profile Ballhead XB-28 Model: XB-28 Ball Diameter:28mm Pan Base Diameter:40mm Height:67mm Net. Weight:190g Max Load:4.5KG Bottom thread: UNC3/8"" Clamp Type: Screw-Knob Clamp ."