This is a special thread that glows in response to ultraviolet light. Fabrics are woven with warp and weft threads.
Under normal light, these do not light up and their presence remains unknown.
It is difficult to obtain this thread and routes to obtaining it are clear.
Barcodes and serial numbers and other distinct individual codes and numbers can be shown with these woven labels.
These are used for individual management of uniforms and limited-quantity products.
With special ink that glows in response to ultraviolet light, this is also used in paper currency and passports, etc.
Under normal light, these do not light up and their presence remains unknown.
Also, it is difficult to obtain this ink and routes to obtaining it are clear.