FH-100AK-00 has detent to hold lever open or closed FH-100BK-00 has spring to return lever to the closed position Both models have rubber bumper inside to reduce noise when closing Includes 1/2" long screws (M3 12).WARNING: This product can expose you to cadmium, lead, nickel, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65WARNINGs.ca.gov.