Specification of our right angle prisms/rectangular prisms as follow:
*Material: BK7 glass or UV grade fused silica
*Dimension Tolerances: +/-0.1mm
*Angle Tolerance: +/-3 'or 30” 
*Clear Aperture: 90%
*Surface Quality:60/40 or 20/10
*Surface Flatness: lambda/8 or lambda/4 at 633nm
*Chamfer:0.3+/-0.1mm
*Coating Optional
Rectangular prisms(right angle prism) are used to deflect a beam of light through 90 or 180 degrees. This can be used as component to create various optical devices.Rectangular prism/right angle prism is often used in telescope,periscope and other optical system.BK-7 can be used for a range between the visible and infrared light.Fused-silica can be used for a range between ultraviolet and infrared light. China star optics offers a wide range of different materials and different degrees of precision prisms.