Tests have proven that blue/green light is most visible to fish in low light conditions. Our Niteglow grubs contains high grade luminous additive giving a glow time of up to 8 hours when fully charged. Charge the grub for approximately 1-2 minutes, slowly rotating it in the beam to ensure all areas are fully charged. Charge times will vary depending on the type of torch being used. We recommend that you use our U. V. torch sold separately, for charging within 15 seconds.