It's not permanent like laser (although laser isn't always permanent either), and they advertise them as 'Permanent hair reduction'. It's basically a hand held unit, sends a flash of 'Intense Pulsed Light' over the area you treat, I can treat both legs in under 30 mins, bikini less than 5.

This light gets absorbed by the hair shaft and within a week or so it sheds, over time and regular treatments the hair doesn't grow back so it's just a case of top up treatments to keep it at bay. I'm told that if you cease treatments it'll come back within a few months though.

I'm happy as there is no regrowth unlike waxing/epilation (used to hate that itchy feeling when the hair pushed through the skin!), and it's a fraction of the cost of laser. Like laser it works best on dark hair/pale skin combos.