Paulson's DK7-X.250 face shield is made of Lexan and designed for a universal fit in ACH, MICH and PASGT helmets. 6 inches in length, NIJ 0104.02 & MIL-V-43511C Certified with a V-50 impact rating.
See other riot face shields here: http://www.paulsonmfg.com/products/tactical/Paulson-DK7-Series-Riot-Face-Shields