The Empire/ Invert Vents Thermal Paintball Lens is ideal when you are using your mask for long periods of time. The thermal system provides anti-fog protection in even the worst conditions. This means that you spend less time with off field maintenance and get more performance during extended play. The Empire/ Invert Vents Thermal Lens fits the Empire E-Vents and Invert and BT Avatar, Cylus and Helix paintball goggles. There is an Empire/ Invert Vents Thermal Replacement Paintball Lens for every situation. Clear is the best all around lens if you never know the conditions you'll be in from one game to the next. Yellow and Amber tints are good for bringing out contrast on overcast days. Smoke is good for reducing glare on bright days and Ninja for reeeally bright games. Mirror lenses are not only smoke tinted but have a super stylish reflective finish for that ultimate eye-catching look!Always change your Empire/ Invert Vents Thermal Replacement Paintball Lens at least once a year. You also need to change your lens any time they get a deep scratch or take a direct hit at 20 feet or less. Safety first, fun always!Empire/ Invert Vents Thermal Replacement Paintball Lens features: - Dual pane thermal lens design for ultimate fog prevention- Tough antiscratch coating- Fits the Empire E-Vent, E-Flex and Invert/ BT Avatar, Cylus and Helix goggles