The Sentinel Keylock HMS Carabiner by DMM. The Sentinel is one of the lightest mini HMS locking carabiners on the market, but more than that it is a really good multi-functional locking carabiner that works really well as a both as a small HMS and also, because of it's slightly offset shape, works as a great rigging/multi-purpose screwgate.
This is because we have used a slightly offset design that increases strength and directs heavy loads into the spine, but uses gently curved top bar with a generous rope radius that allows it to work well with both single and double rope controllers.
The Sentinel works really well with all our belay devices - the Bugette, the Bug and the V Twin and it fits snugly on most belay loops reducing the likelihood of cross-loading.
The Sentinel was redesigned in 2008 to feature a keylock nose so that it clips and unclips smoothly without snagging. It has a deep basket and good gate opening making it a fantastic and versatile rigging biner too that will take a couple of chunky clove hitches.
All the usual DMM refinements are present - fully anodised, full strength barrels to resist push-in forces and conservative 3 sigma ratings.