This four paddle version has two paddles with plus lenses and the other two for the minus lenses.

Optics on both are 0.5, 1.0, 1.5. 2.0, 2.5, 3.0, 3.5, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0 and 12.0.

Lenses are 16mm (1/2 inch nominal) diameter and are recessed to help prevent scratching.  

Lenses are glass for greater accuracy and durability. Comes with qualified aluminum case.