Specifications:
Lens Construction: 8 Elements in 8 Groups
Maximum Diameter: 111.0mm or 4.4 Inches
Length: 144.5mm or 5.70 Inches
Filter Size (Front): 30.5mm
Minimum Focusing Distance: 3.5m or 11.5 ft.
Fixed Aperture: f/8
Lens Type: Manual
Weight: 1000g
T-Mount Adapter Required and Included
This Lens is compatible with all DSLR Cameras

Mirror Lens is a high-quality， computer designed product that incorporates the merits of both reflex optics and refraction optics. This combination provides the user with an extremely sharp picture with minimum color aberration.
While this lens is designed for high definition telephoto photography， it is also one of the most affordable precision optics available， which allows anyone on any budget to enjoy shooting crisp， clear telephoto pictures.

Package Include:
900mm f8 Mirror Lens
Nylon Lens Pouch
Front and Rear Lens Caps
pentax pk T-mount Adapter(you need to tell me your camera brand)