What is this thing?

Hi, I received a 4MB PCMCIA ram card off of eBay today. It's by Amitek and is for the A600 & A1200. It is known as RAM 6040 and has the serial number A010100. It states on the back of the video box (yes, it's in a video box) that it was distributed in the UK by SDL. On the front of the box it states "4MB populated", what does that mean? However, the main reason for this post is this: Inside the box is (as the seller stated) "a thing". It's a small oblong object with a female 9 pin connector (like a mouse port). On the opposite end is a smal sticker with "K50076" on it. On the top of the "thing" is a chequered pattern in silver which starts about 2cm from either end. It is completely sealed all the way around, no screws or join marks, with the only exception being the connector bit. I even tried shaking it! No sound at all. As stated the seller has no idea what this is and I am totally stumped too. What is it?! Regards, Andrew B aliensrcooluk at yahoo.co.uk