Petzl Vertigo Wire Lock
Big alloy krab with a wide gate opening to allow large wires to be clipped easily. The locking mechanism is a major safety asset in big sliding falls, where karabiners can easily be knocked open by impacts against rock, stemples and suchlike. The lock is easily opened one handed, and engages automatically (but visually check it anyway!).
You could also put these karabiners on your caving cowstails; although you'll want to keep them grit free to keep that mechanism smooth.
Weight 97g. Major axis strength 25KN; minor axis strength 10KN; open gate strength 8KN
Made in Italy.