Features: Material: This Lovefoto super clamp work with magic arm, is made of solid anti-rust stainless steel metal and black andodized aluminum alloy for high durability. Non-slip rubbers on the inner side provide strength and stability. Versatile: The magic arm clamp has a female 1/4"-20 and a 3/8"-16, both the standard fitting sizes in the photo industry for heads and tripods can be used for a variety of attachments. Easy to Control: This precise and durable designed magic arm with locking control knob to release or enlarge the tension which can give all position movement, a great chuck to easily and quickly catch the object. Wide Compatibility: 1/4" screws at both ends of the magic arm, can be connected to a monitor, a LED video light, flash light and others with 1/4" screw hole. Widely Adjustment Range: Max. open (approx.): 38mm; Total length: 130mm. Recommend clamp product: 13mm-30mm in diameter.