BLOX RACING TITANIUM RETAINERS FOR HONDA K-SERIES DOHC I-VTECBLOX Racing retainers are CNC machined from the highest quality titanium available on the market. These Ti retainers are machined to exact specifications and help reduce the overall weight of the valvetrain area. As a direct result of the reduced weight, RPM's are increased. Each retainer provides assurance from premature wear associated with high RPM's and mileage. For maximum results, use with BLOX Racing valve springs and high compression valves.