supply of protection cover and bolt , protection cover for levelling valve as per drg. no. aaa35139 alt-a or latest, item no.-1. mate rial spec. - irs:m41-97, plate thickness - 3 mm. test certificate and warranty certificate required at the tim e of supply. sample should be approved by the consignee before bulk supply. [ warranty period: 30 mont hs after the date of delivery ] ] , galvanized iron hexagonal head bolt fully threaded of size m8x25mm conforming to is 1363 or latest along with suitable nut, one no flat washer to is 2016 and one spring washer to is 3063. hardness grade 8.8 for bolt and 8 for nut. sample should be approved by the consignee before bulk supply. [ warran ty period: 30 months after the date of delivery ] ]