Choosing yours
More than any additional tool, a ratchet can last you an eternity. Quality ratchets can be serviced inexpensively therefore should never wear out. Sockets happen to be interchangeable because they’re all standard. Buy the greatest ratchet you are able, even if you buy inexpensive sockets to get started on with.
Socket release
Sockets will be held onto the ratchet by using a small spring-loaded ball on the side of the square travel. After applying a lot of power, I’ve sometimes found sockets get stuck on the travel and the only path to get them off is definitely to hammer the ratchet on to the floor or even hold it in a vice. Good quality ratchets add a button on the back which smoothly pushes off the socket if you are ready to release it.
1/4 inches – Used for smaller sockets and precision work. Beneficial for dismantling individual pieces on the bench.
3/8 inch – The middle sized, and in my opinion, most readily useful size for general use on a car. A 3/8″ drive can travel sockets of all sizes. It is big enough to apply a great deal of force, but not really too big to match into tight spaces
1/2 in . – 1/2″ sockets are usually employed for nuts and bolts from around 10mm or more. A 1/2″ drive socket can apply enough force to undo all nuts on a car.
Additionally, there are 3/4″ and 1″ ratchets but these are being used on trucks, tanks and industrial machinery.
Tooth count
Inside a ratchet there is a toothed wheel which lets it freely rotate as you tighten the nut. Each just click you hear is a tooth passing the ratchet. The more pearly whites there are, the less movement is needed on the give back stroke. A ratchet with 75 teeth will work Ratchets Wheel considerably faster when compared to a 32-tooth ratchet. Making excessive tooth-counts requires top quality engineering and developing, so as a general guide 
the better quality tools will have a higher tooth count.
Drive sizes
socket-drive-sizes
All ratchets accept sockets using a square travel and mostly there are three sizes of drive. All around the community these sizes receive in inches – even though the sockets happen to be metric.