How do the foam slippers work, how are they assembled?
The best answer is given in the instructional video.
How to choose the right size?
Choose according to the size chart from the simplified scale XS/S/M/L/XL according to your size. If you are on the border between the sizes, we recommend choosing the smaller one. 
Which foam slippers to choose for different environments?
The usable environment is a crucial parameter for choosing the right model for the foam slippers. Use in a different environment than intended significantly reduces the service life. The NACESTY model is intended for interior and exterior use.
Is it possible to use the foam slipper on both sides?
The simplicity of the foam design allows it to be folded in the opposite direction as well. This feature can be successfully used in cases of wet (slippery) floors or wet feet. You can use a thicker sample on the side where more is needed.