SPRK-TS1015/2 - Supertech Dual Valve Springs - 84 lb Seat Pressure. Outer Spring - 27.50mm OD - 21.00mm ID. Inner Spring - 20.00mm OD - 15.20mm ID. 12.00mm Max Net Lift. Will Fit Nissan 300ZX - VG30, VG30DETT Engines. Complete set of 24 Dual Valve Springs, 24 Titanium Retainer's, and 24 Seats. This Package Includes: Supertech Performance Dual Valve Springs # SPR-TS1015/2, Supertech Retainer part # RET-NSR20/T1, and Seat part # SEAT-TS1015. Supertech Performance Dual Valve Springs are made with premium Super Clean Chrome Silicon Vanadium Steel alloy for higher performance and ...