These Safety glasses are Anti fog, Medium Impact, the frame colour is Safety Yellow in the Daytime & Night time colour will change from Safety Yellow to a Bright Luminous Lime Green. The glasses only need to be charged up for 1/2 hour in Sunlight or 1/2 hour under a strong light. The glasses will glow in the dark for 10 hours. This is a great safety feature. Details These Safety glasses are Anti fog, Medium Impact, the frame colour is Safety Yellow in the Daytime & Night time colour will change from Safety Yellow to a Bright Luminous Lime Green. The glasses only need to be charged up for 1/2 hour in Sunlight or 1/2 hour under a strong light. The glasses will glow in the dark for 10 hours. This is a great safety feature.