The bottom diameter is 69mm, using a standard 3/8 wide interface, which can be installed with monopods, tripods, slide rails, etc. Widely compatible with most equipment, such as tripods, monopods, slide rails, etc. Ergonomic design, rockers can be installed on both sides of the gimbal according to personal usage habits, and accessories can also be installed in the vacant quarter screw holes It is compatible with two modes of use. The bowl-shaped model can be used with 75mm tripods or equipment. The advantage is that the level can be adjusted in small steps from left to right. The flat-shaped model is compatible with all 3/8 flat-bottomed tripods or slide rails. This is definitely a great helper for your photography, videography and bird . Colour:black Material:ABS+aluminum alloy Package Contents: 1 x PTZ 1 x Ball 1 x Handle 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.