Laner

The Cassin Twin works, but it's awkward to use and can easily be rigged incorrectly if you're not familiar with it. You don't thread it like you think you're supposed to. Be sure to read the poor instructions and practice with it prior to actual use! Other downsides: it's heavy and somewhat awkward to rack; it only works with thin ropes (only up to about nines). Still, with experience and familiarity, it can be a decent tool.