Quickdraws (or extenders) are used to connect your rope to your gear, or bolts. There are two main types of quickdraws, solid and wire gates.

Wiregates are generally more popular as they are lighter so are great for trad, alpinism and onsighting, where saving every gram is essential. Another plus point is that they do not freeze in winter.

Solidgates still have their uses. They very good for sport climbing, where weight is not so much of an issue, and some people prefer the robust feel to a solidgate.

Other things to consider are the quickdraw lengths and types. Many trad climbers use a selection of long and short draws, usually made from Dyneema so that they can reduce rope drag when they need to. Sport climbers tend to prefer shorter quickdraws with 'clean' notchless noses that make stripping steep routes easier. Chunky slings are also preferred as these are easier to pull on when working a route.

A different type of quickdraw connector are 'Screamers' or shock absorbers, these are stitched in a fashion so that if they are fallen on the stitching is pulled out and the force placed on the piece of protection is reduced. As such they are commonly favoured in those situations where you're relying on marginal protection or when using ice screws that can blow under low forces.