Our breeches are normal in size, but if you are in between two sizes, you should go up one size. The fabric is stretchy but with compression, so they should be really tight when you put them on. Like a pair of jeans and then shape to your body when you use them.
The model on the images is 166 cm and uses x-small.
When choosing size, pick your normal size. The model on the images is 166 cm and uses x-small.