The Bayonet Female on M67 Housing MB1 is a female bayonet that attaches to almost any flat housing lens port or lens holder featuring a 67mm thread. When mounted on the housing or lens holder, it allows easily installing and removing wet lenses (equipped with a compatible male bayonet) from the housing lens port or lens holder with a 1/4 turn. Specifications Material: Hard Anodized Aluminum Dimensions (D x L): 100 x 10.5 mm / 3.94 x 0.4 inch Weight: 66.5 g / 2.35 oz Included in box: Bayonet, retainer ring wrench and instruction manual Compatibility Compatible with almost any housing flat lens port featuring a 67mm thread Compatible with the Fantasea Lens Holder 67mm for UL arm (Cat. No. 4071) For compatible male bayonets, please see the Bayonet Mounting System Chart below.