Fotodiox Pro, WonderBurst HSS8000 High Speed Radio Flash Trigger Kit for Canon Pro DSLRs (3C), fits Canon EOS 10d, 20D, 30D, 40D, 50D, 7d Capable of Sync Speeds of over 1/8000 sec When in "Flash" Mode 2.4GHz Frequency with 16 Selectable Channels and up to 300ft Range Wake-Up Function to Wake Up Majority of Flashes from "Sleep" Expandable with additional Receiver available for purchase 24 Month Manufacture Warranty