OTTO Excavator Parts Nkr77 4Jh1 Cooling Water Bypass Pipe 8973127300 897312-7300 8-97312730-0 For Isuzu Durable 8-97312730-0 pipe fits OTTO Nkr77 & Isuzu 4Jh1. Resists mining dust/heat, pressure-stable. Ensures steady engine cooling for non-stop heavy work.