Flukers Screen Cover Clips firmly secure screen covers to reptile and amphibian terrariums prevent escapes while still allowing you easy access. They install in seconds and are adaptable to any screen cover or terrarium. Keeps terrarium screen covers firmly secured Prevents pet escapes while allowing you easy access Installs in seconds Small Clips - Recommended up to 29 Gallon Screen Covers Large Clips - Recommended 30 Gallon & Larger Screen Covers Premium Clips - For All Tank Size Screen Covers Installation requires no extra hardware or tools.