The best belay locker available
This carabiner is the best belay carabiner on the market for a few simple reasons:
1) Its perfectly round, polished, stock makes feeding rope luxuriously smooth - especially while autoblocking with a Reverso 3 or ATC Guide.
2) It is just the right size - large enough to do a double rope Munter rappel, but compact enough to sit nicely on your harness.
4) The Red warning stripe gives a strong visual clue as to whether or not the carabiner is fully locked
3) The Keygate allows the Attache to navigate through all kinds of webbing without snags
Although the Attache does have flaws, they are minor.
1) It has a relatively low, but still sufficient, gate-open strength. This rating is not as important for locking carabiners as for non-lockers.
2) The anodized coating (the blue especially) blackens ropes, I prefer silver.
3) It is heaver than some other options (Vaporlock, Attache 3D, etc)
When used for its intended purpose, this is one of the best designed carabiners money can buy.