I have tested the Volumaster Pro. My hair is quite thick and long, even though the actual hair strands are quite thin. The device itself is very user-friendly and easy to understand. You can lock it with a button on the back so that it doesn't stay open. And then there is an on and off button. The idea is that you should "crimp" the hair underneath to raise the volume on top. The wave on the device is such that you should use the largest "wave" closest to the scalp. It comes with a small instruction on the device. I think this device could work well for someone with slightly thicker hair strands because on me, it shows very well that I have crimped the hair underneath. I took a section and held it for 2 seconds as explained. My hair held the crimp incredibly well! But I don't know if I think the volume got much bigger. I tried to comb over the hair afterwards as recommended, but the crimp sat so incredibly well in my hair. I had to go over it with a straightener to calm down some parts, but incredibly, my straightener couldn't help me. The pattern sat well, both good and bad. I tried to start even lower on the other side so that the crimp wouldn't show, but then I didn't get much volume either. It was a strange balancing act on my hair. I probably won't use this device much, but that doesn't mean I don't think others could get good use out of it. #LYKOINFLUTESTER #OBHNORDICA #BJÖRNAXEN #STYLINGTOOL #VOLUMASTERPRO