The single module RCBOs are a combination of B Curve MCB and an RCD. This provides overload and short circuit protection as well as earth fault current protection in one device.A combined MCB and RCD allows earth fault protection of a single circuit, and helps reduce nuisance tripping of other circuits, i.e. avoids unnecessary inconvenience and improves safety in the home. For example the lighting circuit remains on whilst a problem with another circuit is disconnected.All RCBOs have a positive contact status indicator, i.e. when green window is visible this indicates that there is a 4mm contact gap. · · · Stylish modern profile, matches all other BG devices · · Single module · · Positive contact status indicator · · Available from 45 to 55A