Optional Size:
S: Inner Ear Distance: 3cm/1.2inch
Outer Ear Distance: 11cm/4.3inch
Head Circumference: 18cm/7.1inch
M: Inner Ear Distance: 4cm/1.6inch
Outer Ear Distance: 13cm/5.1inch
Head Circumference: 21cm/8.3inch
L: Inner Ear Distance: 4.5cm/1.8inch
Outer Ear Distance: 18cm/7.1inch
Head Circumference: 28cm/11.0inch