1. Super crab clamp is made of solid anti-rust aluminum alloy for high durability. Non-slip rubbers on the inner side provide strength and stability. 2. It has a female 1/4 inch, the standard fitting sizes in the photo industry for heads and tripods can be used for a variety of attachments. 3. If equipped with a magic arm, they will be able to connect to a monitor, a LED video light, flash light and others. 4. Easy to use: The multi-function double ball adapter only needs to tighten the middle knob, and all the ball heads of the connecting parts can be fixed at the same time. and an extra elastic knob is included for easy removal of photographic accessories. 5. Durable and portable: The magic arm holder is made of CNC-processed aluminum alloy, which has a good hand feeling. Small and portable, durable.