TS3019 Wireless multi-camera tally system (4 Lamp)
Cerevo CDP-FT01B FlexTally Wireless Tally Lamp System
Cuebi Wireless Tally Lights with USB Cables & Straps
Amazon.com : Cerevo FlexTally Tally Light System for Multi-Camera Setup - 433MHz Wireless or Serial Connection - 1 Station Connects to Video Switchers and 4 Lamp Units Connect to Each Camera : Electronics