Compatible with Apple airport express?

I’m thinking of getting a new router as mt netgear one is G.  I have an iMac, iPad and iPhone so like my apple products. 

Im looking at the airport express which states it won’t support an external hard drive. However I believe they are referring to a USB drive whereas the my book live is Ethernet.

My assumption is that that it will work but thought I’d check on here first

If you mean 2012 Apple Airport Express, then yes, it works together with My Book Live, I have this combination at home.

But beware that this Base Station has only two antennas (max. 300Mbps@5GHz) and it does have only one (non-gigabit) Ethernet LAN port.