Interactive Glow In The Dark T-shirts A unique interactive t-shirt for both adults and children; Using the included UV keyring, mobile phone torch or blue laser pen you can create your own designs on the clothing - again and again! They are perfect for everyone - whether you're at a festival, at home with the family or out with the friends. The glow effect lasts between 5-10 minutes, before fading away completely, this means you can keep interacting with the t-shirt throughout your day or night.