3 Select Quality Large Turbo Hermit Crab Changing ShellsSize Range: 2" - 2 1/2" (51-77 mm)Opening Range: 7/8"- 1 1/4"Great for Medium to Large Hermit Crabs. Shells include select quality Turbo Shells with clean and smooth, round Openings. All Natural Seashells, Aquarium Safe.