Filter Element Element Material Pleated Cellulose Compatible Manufacturer Part Number 15 hp to 50 hp UP6-Series Units Compatible Grainger Part Number 1NPK9 1NPL1 1NPL2 1NPL3 1NPL4 1NPL5 1ZPT2 1ZPT3 1ZPT4 3HGC3 3HGC4 3HGC5 3HGC6 3HGC7 3HGC8 3HGC9 3HGD1 3HGD2 3HGD3 3HGD4 3HGD5 3UB84 3UB85 3UB86 3UB87 3UB88 3UB89 4RU68 4RU69 53RU34 53RU35 53RU40 53RU41 6WA82 Inside Diameter 2 5/8 in Outside Diameter 5 in Filter Rating 3 micron