In protecting an LED or photovoltaic cell circuit with a clear cover, a piece of glass does a great job. Alternatively, a see-through encapsulant could be used, and in this case, the “clear” choice is Resin Designs Urethane 53051. This tough polymer has high moisture resistance, and very importantly, does not yellow with long exposure to light, including UV. With an operational temperature range of -50° to +110°C, this robust polymer will tolerate most any environment. It is a two-part material that gels up in just a few minutes after mixing and cures completely after 24 hours. If desired, curing can be accelerated with exposure to heat. For more information, download the technical data sheet or contact us.