Yongnuo YN-622 7-Channel Wireless E-TTL Flash Transceiver for Canon (2-Pack) System type: Digital FSK 2.4GHz wireless transceiver. AA Batteries Required, best with Polaroid AA batteries. Compatible flash mode: E-TTL (II)/ Manual/ Multi Suit for camera Canon 5D Mark III & flash Canon 600EX (RT) Sync mode: 1st curtain, 2nd curtain, Hi-speed sync Support high-speed continuous shooting trigger.