35 Shell Hermit Crab Changing Shell Pack (Set #3) Sizes range from 1/2"-2" Overall Size Opening Sizes are 1/4"-1 1/4" (all sizes are approximate) Hermit Crabs need an assortment of Seashells as they grow. This set is perfect for very small to medium small Hermit Crabs You will receive shells similar the the ones in the pictures - Substitutions are possible.