Grade level to avoid trip hazard and snow plough damage. 5.Water resistant with service replaceable seal. 6.Fitted with stainless steel retaining bolts for prevention of unauthorised access. 7.Lightweight to reduce injury during opening and closure. 8.Non corroding - non sparking frame and cover materials. 9.Reduced noise under traffic movements. 10high quality black through finish or other color by request. 11.High security options available for use in prisons, embassies, airports and other areas at risk of terrorist activities. 12.Comprehensive manufacturer warranty. Place of origin: China Brand name: Qd Model no.: Mc1258