Mini IR Blaster/Emitter for logitech harmony IR/900 Extender/Smart control/Revue | eBay
Logitech Harmony C-RE4A RF Wireless Range Extender with one Dual Emitter | eBay
Amazon.com: Harmony IR Adapters, Ancable 2-Pack 2.5mm Mono Plug to 3.5mm Mono Jack Connector for Logitech Harmony Hub and IR Blaster, IR Emitter Extenders, IR Repeaters, IR Receivers : Electronics