I'll try to post it, but if it doesn't work, google "expand-n-purge" (in quotes) and the word winterize. The first search item was from the everything4pools site. Click it, and look for the expand-n-purge plug (#v5306), and that's basically what ours looked like. It's about $11 at that website.

sorry tried to post a picture opf ours, but here's the link to the one for sale
http://www.everything4pools.com/prod.../251/2479.html

Good luck
Chris