OTTO Excavator Parts Ex300 6Sd1 Valve Spring Big 1125610526 112561-0526 1-12561052-6 For Isuzu OTTO Isuzu EX300 6SD1 Valve Spring Big 1125610526 – 100% genuine OEM excavator part, perfect fit for Isuzu 6SD1 engines. Bulk in-stock, fast global shipping. Superior elasticity & fatigue resistance vs aftermarket big springs, cuts rework & returns, boosts resale profits for wholesalers & agents.