This model is designed to be used with the WMYCONGCONG HC-SR501 PIR Module (Pyroelectric Infrared Motion Sensor Module Detector for Security Use) sold through Amazon. It may or may not work with other manufacturers models.

It has mounting posts inside the enclosure that are designed to be melted to hold the PIR module in place. The posts can be melted using a soldering iron, wood burner, or other hot metal devices (such as an heated up screwdriver tip) - Obligatory Warning: Make sure to do this in a well ventilated area to avoid inhaling whatever toxic fumes may be produced when melting the posts.

The enclosure is designed to be mounted on its bottom side or on its backside with #6 screws. The lid snaps into place and is held by friction if the unit is mounted on its bottom side, though something could be mounted through the backside mounting holes to hold it in place if necessary. When mounting the unit on its backside the lid is held in place by the backside mounting tabs and pressure.

There are two lids, one is for use with IDC connectors. This lid is thinner and can be used with Dupont connectors if you are going to mount the unit on its bottom side. The one for Dupont connectors is thicker (by 4mm) and is only needed when using a Dupont connector and mounting the unit on its backside as there needs to be additional height for the connector and wires to be routed out.