What is the model number for the motion sensor in the SKQH652?

The SKQH652 motion sensor alarm & alert contains a main alert, a motion sensor SKQH652QKP3. This motion sensor works only with the SKQH652, not for other motion alert set we have. And the other motion sensor SK615 doesn't work with this SKQH652 set. 

The compatible AC adapter model number is SKQH652CHG. 

Please note that the SKQH652 can be operated with AC adapter alone, or on batteries alone. It cannot switch automatically from AC adapter power to battery power when AC power is interrupted. You have to remove the plug from the receiver so that the receiver can run on battery power.