indoors only, get a wet tumbler if you do any amount of reloading. at one time i dry tumbled indoors, in my spare room for years. got a job working with lead, and lead testing was required, my lead levels were fairly high. several years of that job killed my reloading time, and my lead levels dropped 30%. they may not seem dusty, but guarantee'd you are getting lead dust from a dry tumbler. only thing i use a dry tumbler for any more is taking lube off sized rifle brass.