Netgear prosafe modular power supply unit 250w ac aps250w is compatible with select managed switches such as m4300 8x8f xsm4316s m4300 12x12f xsm4324s and m4300 24x24f xsm4348s these m4300 series switches come with one psu pre installed another aps250w in full width models second psu bay can be combined for 11 power redundancy or 11 power expansion