The 12mm Boa HMS has all the versatility of its alloy sibling, but has a rated strength of 40kN. It can be used for many applications where a large gate opening or high internal volume are required. The smooth rounded internal form is very useful when rotating the carabiner through attachment eyes, and the basket curves nicely to allow central hanging of loaded components.

HMS connectors are pear shaped and often have similar characteristics to ovals in how they deal with loaded components, i.e. they also allow devices and connectors to self-centre. Moreover, the extended basket allows for additional component connection. Knots in a system such as an Italian hitch can rotate easily between taking in and paying out (even with larger diameter ropes). In general, HMS connectors are slightly oversized to accommodate the added volume of bigger ropes and to feel secure in a gloved hand.