UCL® - Our "flagship" lens introduced in late 2002 is constructed from low-iron float glass (aka water-white) and has a mulit-layer broadband anti-reflective coating applied to both sides. The combination of water-white substrate and anti-reflective coating makes this lens a top performer and the only choice for those looking to achieve the best optical performance. Please note that UCL® glass is ONLY manufactured by Flashlightlens.com and sold on this site or by an authorizerd reseller.

Light transmittance: 98% to 99%
Substrate: Low iron, water-white float glass
Coatings: Multi-layer broadband AR - 2-sides
Thermal durability: Good - typical of most glass

Borofloat® - Manufactured by Schott, this glass is Flashlightlens.com's workhorse. This glass is similar to Pyrex® in that it is a borosilicate type of material and able to withstand extreme thermal shock. That's where the similarities end. Unlike Pyrex®, this glass is manufactured using Schott's Microfloat process. This produces a piece of glass that's virtually flawless and has mirror-like surface quality. Since 2002, when Flashlightlens.com introduced this type of glass to the flashlight world, many manufacturers have seen the benefits of Borofloat and now make this glass standard on their lights. It's outstanding mechanical, thermal, and optical properties make it a great choice for those not concerned with achieving that extra 5% of light transmittance that UCL® provides. This lens is also the preferred choice for those building "extreme" lights that produce high amounts of heat.

Light transmittance: 94%
Substrate: Microfloat borosilicate
Coatings: None
Thermal durability: Outstanding