Please measure your foot as shown in the photo and write in the notes of your order how many centimetres long your foot is.  
Please trace your larger foot, and measure from the longest toe to the centre of the heel.   
In the case of this tracing, the foot is 24.5 CM long.  When I have your measurement on hand, I will match your foot measurement to a boot insole of the same size.  

This helps me send you the best fit possible for an internet order when I am not with you in person.