Size weird ... but good quality

I have a thick mattress (30 cm + 1 mattress pad zipped) and I have a hard time finding suitable cover sheets. It is none in the traditional trade: the maximum I find is caps of 32 cm, this is not enough, I've tried, I need the 40 cm in order to put it easily and do not pull the elastic too. Specialist retailers, a caps-fitted sheet 40 cm costs between 40 and 70, which I think is overpriced.

I hesitated before purchasing this fitted sheet because my mattress size 140 x 190, and size 140 x 190 x 40 cm is not available. I decided, therefore, decided to try 2 different sizes to see which is best suited: 150 x 200 x 38 cm and 135 x 190 x 40 cm.

In the end, for a standard 140 x 190 cm thick mattress, I recommend rather one size 135 x 190 x 40 cm for the size 150 x 200 x 38 cm does not really fit the mattress suddenly (contrary to other) ...

For cons, I recommend good microfiber material that is very nice and very soft.
In any case, the price is very reasonable for these atypical sizes.