Black Diamond ATC Guide
One device to do it all, the ATC-Guide offers maximum versatility. It
has a smooth, regular friction side and, for twice the friction, a
grooved side. When you’re belaying from above, the “guide mode” lets you
bring up one or two seconding climbers with ease and control. For
lowering, it has a small secondary hole that you can girth hitch for
more leverage to release the device.