Designed for high rpm, BC valve springs are wound from only the highest grade, super clean, chrome silicone alloy and feature proprietary processing procedures for consistent pressures. BC titanium retainers are CNC machined from 6AL4V round bar titanium to exacting tolerances.Spring Pressure: BC1100 Seat: 1.550" @ 95 lbs / Open: 1.000" @ 235 lbs / Coil Bind: 0.935" (no machine work required)