... 2. PU as core material, easy open. special polyethylene sliding wheel, low temperature resistance rubber seal, aluminum alloy guide ... cleanl, corrosion resistant and durable. 3. All steel screw parts are galvanized, anti-corrosion, easy open, internal and external ... , simple maintenance. 4. Door size will supplied as customers' request. 5.Open direction: can be any side. cold storage sliding door