... offer a fan-free design, which dramatically reduces power consumption and eliminates noise. This design reduces ... 4 Gig SFP, PoE+, Dual Slots of power, Without Power Module)S3700-28TP-PWR-EI Mainframe (24 Ethernet 10 ... 000 or SFP, PoE+, Dual Slots of power, Without Power Module)S3700-28TP-EI-AC Mainframe (24 Ethernet ... SFP, PoE+, Dual Slots of Power, Including Single 500W AC Power)500W AC Power Module