CAMP Guide XL Lock
Here's what other sites are saying:
Bring the beefy Camp USA Guide XL Lock Carabiner to climbing crags for belays and anchors. This carabiner comes with either a twistlock, screwgate, or triple-action twist to give you the amount of security you want, and the keylock nose makes cleaning simple no matter what.
The C.A.M.P. Guide XL Lock Carabiner is an oversized version of the popular Guide carabiner with a unique shape that gives it an excellent strength-to-weight ratio and a huge gate opening for easy handling with ropes and rigging. An excellent choice for search and rescue applications.