The SF6 insulated switchgear is suitable for middle voltage power distribution system with a rated voltage of 12kV. It could be used as RMUs in a power supply network, fault isolating switches and sectionalizing switches. If equipped with distribution automation devices (FTU/DTU) and communication devices, the SF6 insulated switchgear could communicate with the control center, measure the cable voltage, current, etc, and monitor the working status of switches. BKRM6- 40.5 series of ring main unit is SF6 gas- insulated metal common tank enclosed switchgear, consisting of load break switch unit, load break switch fuse combination electrical unit, vacuum circuit breaker unit, and the incoming line unit of bus. It adopts a range of advanced technologies and materials, with excellent electrical and mechanical properties, less affected by environment and climate, in small size, easy to install easy to operate, with no need of maintenance, and can be flexibly combined. Its clear and intuitive design ensures simple and direct operation, the feeder's connection capacity is large, suitable for a variety of wiring systems. Besides,we can replace the SF6 gas with nitrogen(N2 gas) that it will become a environment protection green gas insulated switchgear. The green gas insulated switchgear safer and environmentally friendly more than SF6 GIS and it will replacing SF6 GIS in the future.