I'm calling on the combined experience of ETS to help me with a problem. I'm looking for a locking carabiner to use as a keychain. Ideally it should be between about 2.5" to 3" long (some flexibility in my spec). As I shop around I see that the ones for climbing almost never list the dimensions, which is problematic for someone looking for one for EDC use.

Cost isn't a big concern since I only need one of them. But it has to be good quality. All the cheapo, small ones I've seen are pretty flimsy and have one fatal flaw- the locking nut is too loose and tends to back down or go past the end of the arm.

Anyone have a suggestion for one that will stay locked and that's the right size for keys, a small light and pocket knife?

http://www.amazon.com/DMM-Phantom-Carabiner-Gold-Gate/dp/B002DIDO4Q/ref=sr_1_1

Specification can be found here

http://www.rockrun.com/dmm-phantom-screwgate/

Overall length is 93 mm or around 3 1/2 inches but is very light weight when rated for over 5000 lbs

I don't think you're going to find a climbing carabiner that small. The ones I have (not that I climb any more!) are more like 4 inches for the smaller non-locking ones. The metal diameter is a little less than your pinky finger. You would have to put a 1/2" (maybe 3/4") split-ring on the key and then clip the split-ring to the biner.

Have you thought about something like this instead of a biner?

http://countycomm.com/ring.html

Yeah, I don't think a "real" biner can be found much under 3". I do have one of those cable rings; it's not bad but not exactly what I need.

The problem with locking climbing carabiners is the size of the screw (or twist, ball, magnet, pinch lock, etc). The lock must have certain strength to pass tests, so they are pretty big.

This is a problem when you combine these with the keysrings. If makes it very hard to slide the keyrings (with keys or other stuff on it) over the screw. This means you can only reach what is on top easily, but not the things below.

I really like the steel carabiners from the hardware (and sailing) store. Cheap, small enough to slide key around and build pretty strong.

Tjin is correct about the bulky locking screw, but here is one possible exception: http://www.rei.com/product/840178/black-diamond-magnetron-gridlock-belay-locking-carabiner.

Now this is one expensive dude - thirty bucks!!! This gives me profound sticker shock. When I began climbing, biners were two bucks apiece.

What might work for a key ring is the classic oval non locker made of round stock. I have seen these used as keyrings clipped to a belt loop, etc. These are not made new anymore, but check with your climbing buddies and you might ind one. I hve some around that I don't use for climbing anymore - the gates are stcky, which might make them even better for keyrings...

Just looking at the REI site again, you might try this one: http://www.rei.com/product/847491/edelrid-hms-strike-slider-automatic-locking-carabiner

I have no experience with this particular model, but it is brand new state-of-the-art,rather expensive, and advertised on the internet, so it must be good....

I am not at all sure that you really need the locking feature for a key ring. Dimensions are rarely, if ever, given in most descriptions because biners are a standard size, just large enough to accommodate a climbing rope and a sling or two. You will have to accept a biner that is about 4" in length. I wouldn't even consider the smaller toy biners. In my opinion, they are quite dangerous. Someone is bound to use them in a critical situation, with disastrous results.

i have several of these:

bison design

that i use to attach things to my pack.

the screw lock does not loosen - for me - ymmv

not meant to support weight.

rei has them - $5.00.

The gridlock extra loop thingy is a pain to use. It prevents the biner from being loaded side ways on a climbing harness, but if you want stuff to move freely, it's rather annoying. The magnetron style biners are slightly thinner, but still pretty bulky and the biners with this kind of closure (both from black diamond and skylotec) are pretty big (Large HMS or belay style) biners.



He is not going to use it for climbing, so it does not have to be load bearing. If you are going to climb, I agree to only carry climbing biners.



In my experience those cheap 'not for climbing' aluminium carabiners break pretty quickly. They are just not very durable.

Does the biner needs to be a locking one? I use a small non locking steel biner. I might have been using my current one for a decade now, have not broken it, nor lost keys.

You aren't likely to find one in the size you listed.

How do you intend carrying it? If the lock is at the bottom it will not back down even if loose.

I have a few older largish non-locking carabiners that I use for attaching stuff to bags. The gates have never opened inadvertently, probably because of the fairly strong spring keeping them closed. One I really like is very similar to the Black Diamond Light D Carabiner.