I've posted about them in the past but couldn't find it.. Here's another by someone else..
www.seabreeze.com.au/forums/Stand-Up-Paddle/SUP/EZ-plugs-Where-to-buy/?SearchTerms=EZ,Plugs
Just a word of warning.. They come with a small piece of sand paper and a wet-wipe that's pretty aggressive and will take the shine off a gloss board.. IMO.. don't use the sand paper or the wipe.. Just clean the surface and peal the backing off and stick them on.. The sand paper and wipe is for using them as a leash plug so you don't pull the paint off the board.
DJ