The area of the seating position contacted by the 3 DH machine shall be covered by a muslin cotton, of sufficient size and appropriate texture, described as a plain cotton fabric having 18,9 threads per cm$ and weighing 0,228 kg/m$ or knitted or non-woven fabric having equivalent characteristics.
Površina sedežnega mesta, na katerem je postavljena 3 DH-naprava, se prekrije z bombažno tkanino, ki je dovolj velika in s primerno teksturo, opisano kot čista bombažna tkanina z 18,9 vlakna na cm2 in s težo 0,228 kg/m3, ali pleteno ali netkano tkanino z enakovrednimi lastnostmi.