These are turbo shells and are a bit heavier than tapestry shells. Most Purple Pinchers prefer these shells, other species of crabs will also wear these shells. Crabs should have at least 5 extra shells in a variety of sizes per crab.
Colors and sizes vary, but the opening size will be what you choose. Some shells may have small chips on the opening. Crabs will still wear them as is.
All shells are the approximate size and have been measured. I measure by inches. So .90 is .90/1 inch
Any questions please ask before purchasing.