Standards are changing all the time. Sim cards used to be the same all over. now, with the increased use of Microsim cards, you may occasionally want to put your Microsim card in an older "regular sim" phone. One of the most economical uses of this item is to save the money on your iPad data plan by using your iPhone 3g or 3gs sim card in it. Please note do not put the sim adapter in your iPhone WITHOUT your microsim card.
I can't complain, but I do want to warn others. Do not put the sim adaptor in your phone without a microsim inserted in it. I did this thinking it a safe place to store it while I was using my other phone and it got stuck. It wouldn't come out adn when I decided just to pull it as (I'd tried everything else) it pulled some metal teeth out from within the phone. which is now broken. Its a perfectly fine adaptor, just store it someplace other than the sim slot if you're not using it.
Just alright. Sometimes it doesn't work when I put it in, but if I switch off and on the mobile phone and I move a little the adapter, it works. For the price, alright.