Widely used as the substrate of choice for Egyptian tortoises (testudo kleinmanni), oyster shell is a calcium based substrate that is normally very dry and is easy to spot clean. Here at tortoise supply, we only use this with Egyptian tortoise juveniles and adults. Other species we typically use other substrates with.
This is purchased by the pound, so use the drop down box to order as much as you need. For calculations, one square foot that is 1 inch deep uses about 4 pounds, so if your enclosure is 24x36" and you want it 1" deep, you will need about 24 pounds.