ight Angle Prism can be used to bend a beam by 90 degree or 180 degree, depending on which face is entrance face. Please refer to following image to see how it works.
Now Crysmit can provide right angle prisms from 0.5mm to 50.8mm size.
Special size can also be offered upon request.

Attribute                                       Specification
Material:                                     N-BK7, Fused Silica,N-SF11,etc
Dimension(mm):                               1.0*1.0*1.0~300.0*300.0*300.0
Dimension Tolerance(mm);                  +0.0/-0.2 (General), +0.0/-0.05(High Precision)
Clear Aperture:                                 >80% (small size),>95%(large size)
Angle Tolerance:                               <3min(General), <3sec. (High Precision)
Flatness /633mm:                               /2(General), /4(High Precision)
Surface Quality:                                60/40General), 10/5(High Precision)
Bevel(mm):                                       -0.1 to 0.5
Coating:                                         Uncoated ,AR,PR,HR Coating, etc

Crysmit offer many types of prisms, include Right Angle Prism, Penta Prism, Beamsplitter Penta Prism, Corner Cube Reflector, Porro Prism, Dove Prism, Rhomboid Prism, Brewster Prism, Equilateral Prism, Roof Prism,Wedge Prism, Pellin Broca Prism,Anamorphic Prism and Custom Prism.