Lid replaces the lid to the built-in drying chamber on FreeZone 4.5 Liter Freeze Dryers to permit use of the Heated Drying Chamber 7521000, 4-Port Manifold 7522200, 20-Port Manifold 7522300, 48-Port Manifold 7868500 or Clear Chamber 7867000. Includes 3/4" thick, clear acrylic cover with 3" diameter opening and gasket and acrylic plus with gasket (for periods of non-use).