This is a Crabtree Starbreaker 363/S030 63A 30mA split load RCCB RCD. It is a grey ABS/plastic clip-on device suitable for interior use. With a screw terminal electrical connection, it has an on/off operation method and Type B tripping characteristics. The RCCB has a maximum amperage of 63A, is for AC current type, and operates at 201-250V. It includes a switch and push-button control style, with an instantaneous break time, designed for electrical wiring applications.
eBay