Self locking (or assisted braking as Petzl say) and therefore very safe (if used correctly) belay device, but only for use with single ropes. It is more compact and lighter than the original version and takes a wider range of ropes. Designed for (and perfect for) sport climbing and indoor wall use.
The belay technique that should be used is identical to classic belay systems, ie both hands on the rope. A fall is stopped by tightening the hand on the free end of the rope, the internal cam pivots and pinches the rope, increasing the braking action until the rope stops sliding.
In addition the Grigri 2 has a new design that allows excellent control during the descent. One hand holds the rope and the other uses the handle to unlock the cam. The handle design allows a very gradual release of the rope and, in combination with the strong braking action of the cam, it gives a great feeling of control when lowering a partner or abseiling. For extra safety, diagrams showing correct rope installation are engraved on both the interior and exterior of the device. The construction includes a stainless steel friction plate and cam to ensure a long life for the product. NB Moving parts belay devices do need lubricating occasionally - don't let it get to a stage where it seizes up mid-use!
Having tested the new Grigri, we agree with Andy McCue who wrote in Climber (March 2011), "... certainly more than a cosmetic update to the old Grigri, with significant savings on weight and size, better handling of skinny sub-10mm ropes and smoother and more reassuring action for both paying out slack and loweiring a climber."
For 8.9 to 11 mm single ropes (though ideal at 9.4 to 10.3 mm).
185g (it is 25% smaller and 20% lighter than the original Grigri).
Tested by Needle Sports staff in Spain using a 9mm single rope and described as "Most impressive - both paying out and taking in were very smooth without the snatchy feel you got with the old Grigri, arresting a fall was straightforward and lowering down was very smooth".