Board Thread:Skyrim/@comment-112.198.82.147-20130613060704/@comment-9028463-20140818051911

Pink Slim wrote: if you have dragon born you can find the hunters of... something crag, that sell you some rings that give your werewolf form some extra abilities, one of which allows you to regen stamina and/or health (can't remember exactly)

You're looking at the Hunters of the Frostmoon Crag along with the ring of the Frostmoon Hunt that let's your beast form regenerate health.

There are actually three other frostmoon rings, one which lets you deal 50% more damage to enemies at the expense of being 50% weaker to enemy attacks, another which extends the duration of your howls by 25% and then there's the one which after transforming, the world seems to slow around you for 20-30 seconds*.

(*cannot remember whether it was 20 or 30)