Choosing yours
More than any additional tool, a ratchet will last you an eternity. Quality ratchets can be serviced inexpensively and so should never wear out. Sockets will be interchangeable because they are all standard. Buy the greatest ratchet you are able, even if you buy inexpensive sockets to start with.
Socket release
Sockets will be held onto the ratchet utilizing a very little spring-loaded ball on the side of the square 
travel. After applying a lot of power, I’ve often found sockets get stuck on the travel and the only path to have them off is usually to hammer the ratchet on the floor or even grip it in a vice. Good quality ratchets include a button on the trunk which effortlessly pushes off the socket while you are ready to release it.
1/4 inches – Used for smaller sockets and precision work. Valuable for dismantling individual elements on the bench.
3/8 inch – The center sized, and for me, most useful size for standard use on an automobile. A 3/8″ travel can travel sockets of most sizes. It really is big enough to apply a great deal of force, but not too big to fit into tight spaces
1/2 inches – 1/2″ sockets are usually used for nuts and bolts from around 10mm or more. A 1/2″ travel socket can apply enough induce to undo all nuts on a car.
Additionally, there are 3/4″ and 1″ ratchets but these are being used on trucks, tanks and commercial machinery.
Tooth count
Inside a ratchet there exists a toothed wheel which lets it freely rotate as you tighten the nut. Each click you hear can be a tooth passing the ratchet. The more tooth there are, the less movement is necessary on the gain stroke. A ratchet with 75 teeth will work considerably faster when compared to a 32-tooth ratchet. Ratchets Wheel Making great tooth-counts requires top quality engineering and manufacturing, so as an over-all guide the better quality tools will have a higher tooth count.
Drive sizes
socket-drive-sizes
All ratchets accept sockets utilizing a square travel and mostly there are three sizes of drive. All around the universe these sizes receive in inches – even when the sockets are metric.