Square D All in One devices are single phase power distribution panels ideal for residential use for when the local codes allow main breaker load centers to be mounted outside. These devices come with a meter socket that supports a standard utility meter, a main disconnect and a load center distribution with spaces up to 42 circuits. QO All in One products are single compact solution provides a time and space saving solution for contractors and installers as well as meet a wide range of applications in use today. This accessory is a semiflush flange kit. It is used with ringed or ringless systems rated at 400A only.