Says out of stock but you can email and ask - I'd be pushy.  When I emailed about their 180mhz 3400c main board, they just said out of stock:  http://www.pchub.com/uph/laptop/344-20557-2436/Apple-Newton-eMate-300-Memory-Module.html- $30.18 (with free shipping; but they won't have it, I don't think)

There's also always $170 + shipping - http://newtonsales.com/emate.htm

In any event, the picture through PCHub - which by the way is an incredible site - should show you what you're looking for.