Manufacturer's part #16 MFB 135. Original price: over $300.00!!! Wavelength is 351-355nm (UV), angle of incidence is 45 degree, flatness is 1/10th wave, reflectance is > 99.5%, thickness is 10mm, clear aperture is 45mm, material is BK7 glass. For use with a 3rd Harmonic Nd:YAG laser. Spec test sheet included. Unused, limited supply!!