Feature: 1. With index adjustment button, sliding left and right can set indexing gear 0°, 15°. 30°, 45°, 90°, five gear options, convenient for photographers to carry out continuous constant angle photography around the vertical axis. 2. With 3/8in screw holes, it can be used with a variety of equipment for photography. At the same time, it is equipped with a conversion screw, and it can also be equipped with a 1/4in screw device. 3. Built-in spirit level, horizontal angle shooting or photography is more convenient and more accurate. 4. Using CNC oxidation surface treatment, the surface is smooth, wear‑resistant and corrosion‑resistant. 5. Easy to install and remove, without any difficult requirements even though you use it for the first time. Specification: Item Type: Ball Head Base Clamp Material: Aluminum Alloy Color: Black Product Size: Approx. 83 x 60 x 38 x 26mm / 3.3 x 2.4 x 1.5 x 1in Weight: Approx. 222g / 7.8oz Features: Quick Knob / Anti-Skid Groove / Built-In Level Meter / Base Knob / Index Scale Indicator / Index Scale Adjustment Button / Base Scale 3/8in Screw Hole. Package List: 1 x Ball Head Base Clamp1 x Slotted Wrench1 x Screw 1 x Conversion Screw1 x Hex Wrench1 x Storage Bag