Aquatica 18469 Extension to Port Locking collar has been discontinued, here are some related products you might like:
Extension to Port locking collar
This extension to port locking collar is designed to complement the Aquatica housings which are now all equipped with a port/extension locking mechanism.
This long awaited accessory is compatible with all of the Aquatica bayonet type extension. The Extension to port collar is machined from lightweight, yet sturdy aeronautical grade aluminum is anodized to military specification and made to withstand the rigors of day in, day out immersion in salt water; it is easily and quickly installed on any extension with the provided hex key wrench.
This port locking collar is compatible with all dome ports with a recessed hole on their back plate.