In the product description I read something from 95% cotton and 5% elastane, the latter provides for the "mobility" and the good "going along" the mass in movement. In Einnäher of briefs strangely is something of 61% cotton, 28% nylon and 11% spandex! My guess is that described in Amazon 95% cotton / 5% spandex relate to the pure "stuff" and the other values explained by the fact that the width of rubber was considered. I think that's definitely misleading.
The slip can be washed at 40 ° C. I think white underwear should be at least at 60 ° C-better still at 90 ° C - can wash allowed.
Otherwise, processing in order and the price is justified. Because of the misleading material designation and low wash temperature 4 stars.