The V Twin is DMM's premium belay device. It is made from stainless steel for durability and better heat management. It stays a lot cooler on long abs when compared to it's aluminium counterparts. They spent a long time playing around with the directional teeth in the body so that they allow you to easily control the friction without the side effects of the ropes sticking when you want to pay out quickly. This unit works well on all ropes from skinny 8.0s to fat 10.5s.