This thread uses special phosphorescent dyes that ‘collect’ light while it is exposed to bright light, and then ‘releases’ the light when it is moved into the dark. It has a nice feel. The thread will eventually lose it’s ability to collect light as it goes through the wash, so we recommend using it in locations or on garments that aren’t washed regularly such as hats. The cost of dye makes this thread considerably more expensive than regular embroidery thread. It is especially well suited to hats in night clubs.