Looking for something different? Tired of night diving? Fluorescence will give you a whole new perspective on the world beneath the waves. With Tonelife excitation and barrier filters, you can convert your existing lights into a fluorescence set-up. No need to purchase expensive specialty lights or guided dives. Be the explorer!nWhy yellow mask filter? This is because unlike UV, blue light is not invisible to the human eye; without the filter you will therefore not be able to see the fluorescence because it will be overwhelmed by the ambient light.nWidth 155mm,Height 55mm,Thickness 3mm, Very stronger!!nSuitable for most of Diving mask!!nACRYLIC / PMMA material!!nLooking for something different? Tired of night diving? Fluorescence will give you a whole new perspective on the world beneath the waves. With Tonelife excitation and barrier filters, you can convert your existing lights into a fluorescence set-up. No need to purchase expensive specialty lights or guided dives. Be the explorer!