Over at Onthesharpend.com, Jon talks about choosing a locking carabiner . He makes some great points about the pivotal role of a locking carabiner. 

“Picking out locking carabiners is actually a non-trivial event for a climber because by virtue of having to use a locking carabiner you are signifying that what you are doing is especially important and it needs to be more secure than what a regular ‘biner can provide.”

Also how important it is to test the biner gate before making the purchase, as I have had a couple that stuck easily.

“Not all screwgates are created equal, some are a lot smoother than others. I play around with the actual ‘biner I’m going to buy to make sure it is easy to lock/unlock with one hand and to make sure the screwgate doesn’t get easily stuck at the top or bottom.”

Trango Classic Screwlock Carabiner (Spring 2009) The Classic Screwlock Carabinerby TrangoTakes the Classic Straight Gate Carabiner and add a screwlock collar on it. So no more excuses! Take ‘em along on your shoulder runners - rig a couple of draws with these for first bolts and loan ‘em to your friends. Anodized bodies and “Gate-Lock” design.Features: Gate Open: 7kN Individually Tested Major Axis: 24kN Minor Axis: 8kN Weight: 57gmGM: 57Major: 24Strength Minor: 8Cross: 7