This drum cap also called venting cap, exhaust cover, the combination of breathable cover and so on. Breathable cover is normally provided by a body with a small hole cover, inner lid permeable membrane containing a combination of the breathable film can effectively discharge the liquid barrier effect. Our  cover can balance internal and external pressure vessel, to avoid the container products due to physical or chemical changes produce expansion or contraction.  25 Liter Plastic Containers Caps can used in 25 l Plastic Drums/20  L Plastic Drums .If you need Drum Caps In  Tinplate Please Click Metal Lids Caps Covers, In Plastic Please Click Plastic Lids Caps Covers.