Spielstabil makes two sizes of kids sand sieves that can be purchased separately instead of buying a whole sand kit just to get the sifter. I saw these on line and think that they might be like the one you found to use. I have not ordered any yet...thought you might see if it looks like what you have. funbabytoys.com has them and pictures of them on their site. You can also type in search for Spielstabil sand sieve and get other places that carry them. My wife says our kids use to have one of those when they were small for the sand box...I don't remember it. Probably threw it away when they got bigger. Now desparately looking for one my self!!
Brad