6’x6′ Leopard Tongue Groove Apex Shelter – Sturdy Tongue Groove Shelters. The Leopard Tongue Groove Apex with Sturdy Framing represents an enhancement of one of the favored blueprints in the Leopard assortment. The sturdy framing boasts double the typical thickness of a standard shelter, enhancing the overall durability and solidity – while also allowing for greater interior insulation options due to increased depth. 6’x6′ Leopard Tongue Groove Apex Shelter – Sturdy Tongue Groove Shelters