Mog I should say at least 1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 percent
I am not kidding, the diff is amazing. I washed my hair a couple of weeks ago when it was raining. This is usually a recipe for disaster, I blow dry, use crappy normal straighteners and as soon as I step outside the door, even with a brolly, I look like crazed bag lady.
This time, I rough dried it with a hairdryer then tonged it with the GHDs for about 10 mins and it looked fab. (as opposed to spending about 40 mins drying and tonging) I went out with dd, it rained for 10 mins, I was out in it with no brolly, got home and my hair was STILL AS STRAIGHT AS A POKER!!!
Got a tiny bit frizzy when it dried so I gave it another going over before going out and it was immaculate.
All I can say is buy those tings.