For DOWNWARD OPENING FLAP DOOR used with piano, butt or drop hinges (SDH 001, SDH P,). Short arm type designed for short door applications. SDS C100TV has a catch to hold the lid in closed position. SDS 100TV does not have catch feature. Designed to be used with magnetic catch or touch latch. Non handed. Torque Calculation : Torque = Door Height 1/2 Door WeightWARNING: This product can expose you to acrylonitrile, butadiene, chromium, nickel, styrene, 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.