I got the 1.1mm size for the gaps between my teeth which are quite large. It doesn't fit! It is double the size of the Intermed equivalent and 1.5 times thicker than the tepe! The wire is very thick and hard as well. It seems to be of good quality construction but I can't evaluate if it is durable since it doesn't fit... The price is very competitive and since the Intermed ones I used to buy wear out very quickly, and the tepe ones seem very expensive and small, I will try a smaller size to see if it suits me.