I have been using Mutt Mitts for 9 years now, originally because the town I lived in placed courtesy containers of them at popular trailheads. I later bought them direct from the manufacturer. Well worth the money; absolutely the best dog poop/ biohazard bag (dead rats etc.) I have ever used. The clever Mitt design is actually a heavy duty double-thickness section at the pick-up part of the bag; I have never punctured one even while picking up poop in rocky terrain. My dog is a German Shepherd, so I appreciate the generous size of these bags, unlike the typical pet store bags made for smaller dogs.