If you are after a good quality 125A main disconnect breaker that can be cycled on/off (under full load) for up to 2000 cycles then this is a great solution.
For those after a lower cost HRC option click here
Click here for the more information on this breaker.
Note: if wiring your own system in NZ, you can do so for voltages up to 120 VDC (ELV) if you have suitable knowledge and experience. For LV systems (>120 VDC) this is prescribed electrical work and it must be done by a licenced electrician.