Anthony, do you mean card reader as in the card reader to get the footage into your pc ?
You could use the mxr if you have an express slot as the mxr obviously works with these cards, i bet that the kensington would work also.
I'd also bet that the transcend and sandisk sdhc>usb reader works, i can get the transcend ones for about a fiver.

Paul.

What i mean is.. at the moment I insert my 16gb transcend SDHC card into the Kensington 7-in-1 Media Reader then put that into my EX3.

What I was curious about is, would the ATP promax SDHC card also work with the Kensington 7-in-1 Media Reader for recording with the EX3.