I bought teo zoom led teeth whitening groupons for myself and my son. I researchec and read losds before deciding to go with imperial smile beauty. There teeth whitening is advertised on their website at £250 and lasts 1 hour with 3 15 min sessikns of led light with 3 separate bleaching/whitening put onto teeth. Also cleaning before, after and during. This did not happen, we only got 2 lots of bleaching/whitener with 3 x led light and no cleaning befote, in between or after. I had no noticeable differencd and asked if i was to do it agsin if it would notice bit was told it wouldnt. My sons lightened a bit but was patchy. We have since found a different place thst can gusrantee 10 shades whiter or monry back . Also told me it will work on me.