The SNAP-IT-WM4 wall-mounted polycarbonate enclosure makes it easy to install Opto 22 I/O where you need it, providing convenience and protection for your SNAP PAC System. The enclosure includes an I/O mounting rack and a power supply, already wired. You add the I/O processor and the SNAP input and output (I/O) modules needed for your application. The SNAP-IT-WM4 is a sturdy polycarbonate industrial enclosure that holds one processor and up to four I/O modules. The SNAP-IT-WM4 has a transparent cover. It is a handy size for small areas and mounts on any wall. For the I/O processor, add either a SNAP PAC R-series controller or a SNAP PAC Ethernet brain. Choose the controller if you need programming capability; download the free PAC Project Basic software to program it. If you don't need progammability, choose the Ethernet-based brain, which provides local intelligence and can be used with a SNAP PAC controller, with an Allen-Bradley PLC or Modbus/TCP system, or for PC-based control. NOTE: If you're using a Wired+Wireless I/O processor with this enclosure, purchase a 90-degree right-angle bracket adapter for the antenna. Wired+Wireless models include SNAP-PAC-R1-W, SNAP-PAC-R2-W, SNAP-PAC-EB1-W, and SNAP-PAC-EB2-W. For I/O modules, choose from our complete line of SNAP analog, digital, and serial modules. Each module contains one to 32 points, and a wide variety of signal types is available. If you need an enclosure for panel mounting or outdoor use, see the 12-module SNAP-IT-PM12. For a rack-mounted or desktop enclosure, see the 16-module SNAP-IT-RM16.