The Brand, adjustable relief valve is precision built, dependable and low priced. Both the RL and RLC are of the ball spring type, which is the most dependable type of relief valve. The ball will not jam, lock, or seize and will always open. The advantage of the RLC over the RL option is that cracking pressure at low and high flow is virtually the same. The RLC is also more stable when flow is traveling past the ball and spring.