This is the Trident Aqua Optics Lens Installation Glue Features: Optical clear glue specially formulated for use in dive masks Use to glue magnifying lenses inside dive masks Dries crystal clear Cures in 24-48 hours depending on temperature (75F is ideal) Safe and non-toxic Use only on clean, dry surfaces 1/8 fl oz. dropper bottle Aqua Optics Dive Mask Magnifying Lens Glue is the easy to use glue to reach for when you need to affix magnifying lenses to a dive mask. It&';s better to over-apply glue than to under-apply it, and excess glue is easily removed using cold water and a soft bristle tooth brush. Do NOT use hot water, as this will loosen the cured glue under the glass lens.