It's the difference between maybe getting skin cancer to kissing your b*u*t*t goodbye from a melanoma, don't risk it there is no such thing as a healty tan except maybe from a can.
red, redder, dead
but please take care
I would probably guess thats it 1 -3 is the lvl of darkness and strength of the tan.
Tans like those are bad for you. http://en.wikipedia.org/wiki/Tanning_bed
Spray tans are better health wise.
Brown. Browner. Brownest.