Expand to use more devices Multiple 1/4 in and 3/8 in expansion screw holes meet installation requirements. It is not only for tightening the diving head but also for mounting a monitor and adapter. Anti drop design A twist stop screw on the handle limits the knob rotation. The unit can rotate only until the ball head is adjusted, and the angle cannot be unscrewed to prevent the ball head from falling. Slide rail design The slide rail of the sleeve prevents the ball head from blocking. Older butterfly clips often use screws as guide rails, which can lock a single ball head. This version uses an aluminum alloy guide post as a guide rail to block and clamp the ball joint. Material and function Lightweight aluminum alloy with a corrosion resistant hard anodized body delivers high precision and durability. Function: perfectly connects to the ball head for attaching an auxiliary light, diver torch arm, or action camera during normal shooting and sub-shot. Use scenarios - Underwater or dive filming: attach a diver torch arm and action camera to the same ball head setup for flexible lighting and angles. - On location with monitoring: mount a monitor or adapter for live view and quick framing adjustments. - Studio or travel shoots with multiple accessories: connect auxiliary light and other 1/4 in or 3/8 in devices for versatile setups.