waterproof flourescent sockets

I have seen two types of waterproof flourescent light sockets.

1) The more common type includes wires, is designed to provide electrical
connection only, and comes with a couple of separate c-shaped clamps to
hold the bulb. It appears to be designed and marketed for the aquarium

2) The other type has a removable collar/seal and provides mechanical
support as well as electrical connection. The collars are slipped over the
ends of the bulb, the bulb is inserted in the sockets, then the collars are
twisted to seal and lock the bulb in the socket. I like this second less
common type (which I saw in the San Fernando Valley less than a week after
completing my hood).

I watched a light with live wires almost fall into the water at a local
store when it slipped off the clamp - I don't like the loose type 1

I tried to see if there was a manufacturer on the second type so I could
buy them outside of the aquarium trade, but no luck. They were blister
packaged and cost $15/pair. I think this type 2 socket might be abailable
industrially for a fraction of this cost.

Has anyone else seen these sockets and do you know where to get a better price?