SS. The K44 Duo is a programmable codelock for one or two doors. It is possible to set separate codes for each door or the same code for both. K44 Duo also provides the option of door control and alarm output. The K44 Duo has a code capacity of 20 four-digit codes and 10 six-digit codes. By using the K44 Duo’s tamper switch in combination with the SK5 security unit, it is possible to achieve a higher level of security.. Backlit buttons. Two relay output. Lock open time 1-99 seconds. Two door interlock facility