What is the difference between the types of D-Series enclosures lens?

When designing a lens, there is a tradeoff between material thickness and durability, i.e. the most durable lens bubble will be thicker, but will have lower optical clarity, and a thinner lens will have better optics, but lower durability. The Optically Pure Lens is made for all cameras, and is optimized for 40X optical zoom rates. It will provide the clearest image at full-zoom-rate for any zoom camera. It is made of acrylic, which has the best optical clarity of common thermoplastics. The Optically Pure Lens is available upon request at time of order at no charge, and is also sold separately as a replacement accessory. The tinted lens is also available and can be requested at the time of purchase. The Vandal Tough Lens was made for cameras 27X optical zoom or less, and is also made of optical grade acrylic. The Vandal Tough lens is roughly twice as thick as the Optically Pure Lens, and is much more durable. In addition, there will be virtually no visual difference at or below the 27X full zoom rate. The Vandal Tough lens is the default standard lens on production D2 and D3 models. The heavy-duty "DuraView" (product# KT-CLNS-DV) lens bubble from Dotworkz is a soon-to-be-released lens that can withstand the most stringent impacts. It is made from Polycarbonate thermoplastic, as are all of the D2, D3, and S-Type housings. Polycarbonate (PC) is the same material used to construct football and motorcycle helmets and is extremely strong, shatter-resistant, and preserves these characteristics over wide temperature ranges. This material is also used to make the new F22 Raptor jet-fighter canopy, the largest molded production use of PC plastic. Dotworkz uses this heavy-duty material for extra-tough deployment needs. We are currently recommending this lens option for cameras of 10X zoom or under. It has an extended upward viewing angle, and is ideal for deployments that require the camera to be mounted at lower levels. This option is targeted to be released in the very near future.