All Swivlers use a custom-made pivot ball and socket with a 7/16 -20rolled and ground chrome moly stud.
Pro swivlers use a spring plate with a series of interchangeable bolt-on spring pilot tubes.
The use of smaller or larger pilot tubes lets the racer precisely match the size of the tube to the inside diameter of the spring.
One spring pilot tube is provided with each Pro Swivler.
Spring pilot tubes are available in 1/4″ increments and can be purchased separately.