My Chemical Romance Tease Reunion Newsweek Manley NexTek Series Double w o Damper 16pc Valve Springs 1.640 OD .860 ID. From drag strips to short track and endurance circuits, the Manley NexTek series is engineered for serious racers. NexTek springs resist pressure loss and valve train degradation even in the most demanding race conditions. That means more consistent spring force deep into a run, reduced valve bounce, and improved overall stability for high RPM performance. Built to outperform and outlast in real world competition. Specially processed premium grade chrome silicon that is virtually free of impurities or surface irregularities Available in polished versions to reduce friction, improve fatigue life, and minimize load loss Ideally suited for Sportsman Drag Racing applications Better valve train stability and component life