Hej Totte,
The washer prevents slipping of the knots through the drilled hole in the plastic plug.
The alignment of the knots allows length adjusting of the “brake straps” reflecting cord.
Further explanation needed ? 
B. r.
Hej Totte,
The washer prevents slipping of the knots through the drilled hole in the plastic plug.
The alignment of the knots allows length adjusting of the “brake straps” reflecting cord.
Further explanation needed ?
B. r.