The LX2 replaces the older LX pocket, and is a great new design which adds weight versatility options with an ease of use design. LX2 uses a simple pinch and pull buckle, and large nylon handle on the pouch to ditch or carry the weights.
The pouch itself is zippered and holds 12 pounds total, but is partitioned to isolate weights within the pouch. The benefit there is if you only have say 5lbs in the pocket, the partition will avoid it shifting around during the dive.
This system is also reverse compatible to allow use with older Hollis backplates and harnesses.