These are not only the cheapest locking carabiners Backcountry.com sells, but they are also one of the lightest that feature the snag-free keylock. The only lockers lighter are the WC Neons and DMM Phantom, which will cost you $3-4 more each, a tradeoff of nearly $.50 per gram saved.
I have owned 4 of them and none have had any functional issues at all, they lock and unlock smoothly and the gate spring is strong and even. They work perfectly in pairs for toprope masterpoints, or alone for clove hitching into multipitch anchors and attaching prussiks to your harness. The silver coating is better for the environment and doesn't blacken ropes. I use them everywhere I need a locker, except as a belay biner.
It is the rare case in outdoor gear that you can save money AND weight.