Surgical mask backstrap 口罩帶扣

Surgical mask backstrap 口罩帶扣

In the recent Covid-19 virus outbreak, surgical mask wear become necessary.

Some surgical mask size maybe too large for lady or child.

This backstrap can tighten the mask and improve mask fitting. It can reduce strain caused by mask earloop

If the backstrap is too short, you can stretch it to suitable length. The strap will return original length when heating up to 70 degree.

24-Feb-2020
Mask backstrap 8 cm has 3 1/2 wavelengths.
Mask backstrap 11 cm has 5 1/2 wavelengths.
Mask backstrap 14 cm has 7 1/2 wavelengths.
Mask backstrap 17 cm has 9 1/2 wavelengths.