Skunk2 Alpha Series Honda D Series VTEC Valve Spring SetManufactured exclusively from super clean, chrome silicone wire milled in Japan, Skunk2's Alpha Valve Springs for Honda's D series VTEC engines are a product of the company's years of racing and engine building experiences. Alpha Valve Springs are able to prevent valve float and maintain valvetrain stability at engine speeds in excess of 10,000 rpm. Skunk2 designs, develops, and tests its entire valvetrain lineup in house to ensure superior quality