Bolt protected routes are the norm on the Continent, where they are largely accepted, less so in the UK, where they are by common consensus virtually entirely confined to limestone outcrops and quarries (though not all limestone outcrops, nor all quarries). They are occasionally found on aid climbs and may (even more occasionally) need replacing, though usually modern gear will have rendered them redundant. In fact in the UK, if you are not certain that bolts are acceptable on a particular crag then the rule would have to be don't place them without making enquiries with the BMC, MC of S or MI depending on the area you are in. And it is extremely unlikely that bolts will ever be acceptable in the UK on (a) mountain crags, (b) grit!
Moreover, placing bolts safely requires both skill and an ability to follow the instructions that come with them - it is best to be shown how by someone who already has gained suitable experience.
Bolts come in two types, expansion and resin-in. The former have the advantage that they can be climbed on as soon as they are placed but the downside is that they can easily be stolen. The latter are far more permanent but one must wait for the resin to cure thoroughly before relying on them.
Below is a tiny selection of what is available on the market. Please contact us if you require lower-offs or any other bolting equipment not featured here.