mperature, U.L. listed silicone.  Supplied loose inside the enclosure (not pre-installed).</li><li> Polycarb versions are designed to meet NEMA Type 4, 4X, 6, 6P, 12 &amp; 13 ratings which meet and exceed IP ratings up to and including IP68.  (Except 1554/55 V size which is 4,4X only)</li><li> ABS Plastic versions are designed to meet IP66.</li><li> Lid is secured with included M4 stainless steel machine screws which are threaded into integral stainless steel bushings for repetitive assembly &amp; disassemb