Listing is for One NEW  51mm (2") diameter cemented doubled achromat lens, 180mm focal length, f3.5 FR, BK7 and F2 glass elements.  10.7mm thick the the edges, 14.1mm thick at the center.  Typically used as objective lenses in 50mm binoculars and 50mm finder scopes and spotting scopes.  Lens weight is 70 grams. 

This is one doublet lens, no lens cell or mounting.  Packaged well for shipping. 

Price includes USPS shipping in the USA!

Custom laser cut ABS plastic non-adjustable lens cells are possibly available, given precise specifications. This is a do-nut to hold the glass and adapt it to your tube.  The cost of cells will be higher than the cost of the lens.  Contact us about this ONLY if you already have very specific design details already available.