The BL ll arm has been designed to allow the operator to interchange the spring configuration depending on the size of camera they are flying: The arm is initially set to support cameras ranging from 18lb-56lb in weight. Using the light weight springs provided, the arm can be readjusted to take cameras with a weight from 6lb-26lb. The arm has been designed to work with the connector blocks from the PRO, Master, EFP, Daniel Souve and Sachtler vests. The arm post rod measures 5/16” in diameter allowing it to be used with a variety of other sleds. E.g. 3A, EFP, PRO, MK-V, Sachtler and Chrosziel.