The GR-E2 Grip is fully compatible with the Canon EOS-3 prosumer model as it is designed to accept both the optional PDB-E1 & the newer PB-E2 accessories. The EOS-3 operates with an increase built-in firing rate of 4.3 fps as opposed to the 3 fps by the EOS-1 & EOS-1N cameras when the 6-volt 2CR5 battery is used with the GR-E2 Grip. GR-E2 has an additional protective "door" built-in to protect the 6-volt 2CR5 lithium battery from moisture & cold temperature.