United Poly Engineering [P] Ltd. Manufactures Instrument Tray without Cover. United Poly Engineering [P] Ltd. Is an ISO 9001:2000 registered company. United Poly Engineering [P] Ltd. Supplies stainless steel & plastic hospital hollowware & utensils and hospital furniture. Instrument Tray without Cover is made of stainless steel. Instrument Tray without Cover has been available in the length from 210mm ton 365mm. The width of the instrument tray without cover is 160mm – 265mm. The height of the instrument tray without cover is 25mm-30mm.