I got this Sim Adapter for the case when my iPhone 4 isn't working (and needs some complete restore or some kind of work done by Apple. Has happened on my iphone 3g and 3gs before so i didnt want to run any risk with the new iphone 4). To avoid being without a phone i thought a microsim adapter would make perfect sense to bridge the time without my iphone.
The adapter arrived in a handwritten envelope with nothing in it but the adapter, fair enough. I tried out the 2 adapters i ordered straight away and tried to fit in my microsim. It kind of fit but wasnt very stable. I had my old iphone 3GS lying around and used this adapter to fit my microsim into the iPhone 3gs sim tray (which takes normal simcards without any problems).
As the microsim
a) didnt fit perfectly into the adapter and was sticking out a little and
b)was being quite unstable in the adapter and kept constantly falling out
it was deemed not fit for purpose by myself.
It works fine in a traditional phone with a simcard slot behind the battery. I tried it on an old sony ericsson w850 and while it wasnt a great fit (due to the above reasons) it worked.
My recommendation, if you are getting this to be able to use it in a phoen which has a kind of a simtray (like the older iphone models), then dont do it. You will be disappointed. If you want to use it in a normal traditional phone, its fine and i can recommend it, especially at this price.