(3 Pack) Zoo Med Cricket Block Cricket Calcium and Gutload Blocks. The Zoo Med Cricket Block Reptile Supplement offers an easy way to deliver calcium to insect-eating reptiles and amphibians. It's a no-mess alternative to calcium dusting that boosts the nutrient content of live crickets—aka gut loading. This calcium-based block has added nutrients and vegetables to optimize cricket health and the reptiles that eat them. It's easy to use—just place it inside the cage with the crickets and let them feed.