Features: Double-track rail design to increase the sliding effect, smooth and fast. 1/4 screw on top, with a 1/4 to 3/8 convertible screw to meet your needs better. A built-in spirit level in the sliding block is used to help you find the balance quickly. 1/4 and 3/8 standard screw mount design on the rail for connection with other photographic equipment, such as tripod, ball-head, ect. You can adjust the damping between the sliding block and track rail by rotating its locking knob. Special supporting foot design, height-adjustable, more anti-skid and stable. High-quality aluminum alloy, giving it exceptional strength for heavy duty work.