Non-vacuum cabinets are made of methyl-methacrylate. Cabinets have gasketed door with two metal hinges, two latches and door handle. Includes desiccant tray and dial hygrometer. Auto-desiccator cabinet features a permanent silica gel contained in the control unit. No desiccant tray is needed. The cycle is indicated by a green light for a 4 1/2 hour absorption period or a red light indicating 1/2 hour regeneration of the silica gel. This cabinet will lower relative humidity 30 - 40%. Vertical models have shelf cleats that permit 15 height adjustments; three shelves with vent holes and three sets of shelf rails.