In reply to Slarti B:
They’re marginally bigger than a sentinel. A little smaller than a Petzl Attaché.
The below is super geeky, but it’s why I like them. If I was going to have only one screwgate on my rack it would be a Phantom HMS.
They have the new DMM barrel on the screwgate, which is much nicer that the older version, and works loads better with gloves on.
The top of the crab is nice and round, making for nice slick payouts when belaying. Especially compared to the oblong shaped bar of the sentinel. It also can easily accommodate two clove hitches, and works great with an Italian hitch.
I also never really liked the bend in the spine of the sentinel as I found it created a pinch point if the krab flipped upside down when belaying with half ropes.
All in all I think the Phantom HMS is a big improvement.