HDMI Splitter 1 in 2 Out, 4K HDMI Splitter for Dual Monitors Duplicate/Mirror Only, 1x2 HDMI Splitter 1 to 2 Amplifier for Full HD 1080P 3D with HDMI Cable (1 Source onto 2 Displays) - Newegg.com
1x2 HDMI Splitter - Full 3D, Ultra HD, 4K - Vivid AV® Official Site
Amazon.com: HDMI Splitter 1 in 2 Out 4K @ 60Hz 1x2 Powered HDMI Splitter Duplicate Mirror by J-Tech Digital (1 Source to 2 Displays) : Electronics
Amazon.com: OREI 1x2 HDMI Splitter - Ultra HD 4K @ 30Hz, HDCP, 3D & Full HD 1080P Support for Xbox, PS4, Blu-ray, Apple TV, HDTV - Adapter Included : Electronics