Figure 8

The standard, no frills belaying device from CAMP. It doesn’t get any lighter (except if you skip belay devices altogether and use an HMS). I learned to belay and rappel with it and used it for many years (also using a Cassin plate to belay seconds). Recently I replaced both with a TRE, but I still use it for canyoning or really low temps. It also comes handy when friends want to try climbing for the first time (my old harness also helps here).

Pros:
Really cheap
Really light
Easy to use even with the thickest gloves
Works with a very big range of rope diameters
Can rappel over knots (useful for bailing using two ropes tied together or a damaged rope tied off)

Cons
Kinks the rope (not as much of a problem with singles as with doubles)
Can rappel over knots (like the one at the end of the rope. Use backup)

I don't use this for belay but I do know that it makes a good easy to use rappel device. Also it is fairly cheap and very durable.