It's not cheap but it works. Some reviewers have claimed it is a scam, but its clearly not. I wanted my iPhone unlocked from a Japanese carrier and was told told it would take 5-20 days. It took exactly 10 days from initial registration. The total fee was a bit less than the small print' estimate. Progress is informed daily by percentage of completion and moved around 5% per day up to 50% then it suddenly accelerated from 63% to 100% in 24 hours. I don't know how it is done "over the air" by wifi but my phone is now unlocked and SIM free. It feels like taking a risk while waiting the first time for it to happen, but be patient and you will get exactly what you paid for.