GRIGRI - How to belay the leader
The GRIGRI 2 belay device with assisted braking capability is designed to facilitate belay maneuvers. The GRIGRI 2 works equally well for lead climbing and top-roping. It may be used on all single dynamic 8.9 to 11 mm ropes on the market (optimized for 9.4 mm to 10.3 mm ropes). Both compact and ultra-light, the GRIGRI 2 will accompany you on climbs around the world for many years. The GRIGRI 2 has a new design that allows excellent control during the descent.
Watch the GRIGRI belay device & descender : http://www.petzl.com/en/outdoor/belay-devices/grigri