Think Tank Eyepiece Adapter, Connects Hydrophobia 300-600 to the all Canon SLR's Prior to the Mark III, #EP-C Compatibilty: Compatible with: EOS 1Ds Mk. II EOS 1D Mk. II EOS 5D Mk. II EOS 5D EOS 50D EOS Digital Rebel Series Sony A900 & Sony A700 Warranty: Think Tank warranty