United Poly Engineering [P] Ltd. Supplies Surgical Tray with Cover. United Poly Engineering [P] Ltd. Is an ISO 9001:2000 certified company. United Poly Engineering [P] Ltd. Manufactures stainless steel & plastic hospital hollowware & utensils and hospital furniture. Surgical Tray with Cover is made of stainless steel. Surgical Tray with Cover has been available in the length from 209mm to 370m. This surgical tray with cover has been provided with the width of 158mm – 320mm. The height of this surgical tray is from 76mm to 100mm.