What you need to know about the PoE Passthrough Switch - YouTube
16 Port POE Switch, Unmanaged Outdoor Computer Network Passthrough Powered Router, Networking Internet Ethernet Hub (16 Port PoE+/2 Gig Up-link/1 Fiber SFP) Power Extender Switches - Walmart.com
Amazon.com: Intellinet 5-Port PoE Passthrough Gigabit Ethernet Switch - with 1 x Gigabit PoE Input, 4 x Gigabit PoE Output, 68W Power Budget via AC Power & 26W Power Budget via PoE
5-Port Gigabit PoE+ Powered EdgeSmart Switch with PoE Pass Through - TRENDnet TPE-P521ES