This is the appropriate plug to install in your control box to accept an L6-30R cord end from your power source 240v 5500 watt (up to 30 amps). The whole unit sits recessed into the box/panel so that nothing sticks out. You will need some room in the box for it.
Again, just so we are clear about what this is used for: If you want to have the power source running to your controller be disconnectable, this is how to do it. This way the power cord has female on it to avoid having a double male cord (very dangerous). You will typically have a 3-wire power supply to your panel when it will be run on ONLY 240 volts, that is with no 120 volt components at all. If you need both 240v and 120v in your panel, you will need to use 4 wire instead.
Material of Construction Ethylene Propylene Thermoplastic
Number of Wires 3
NEMA Configuration 6-30P
Note that we source these plugs from several vendors to keep the price as low as possible so the one you receive may not be exactly as pictured. However, it will be a quality brand name such as P&S, Leviton, Hubbel, etc.