Paulson's DK5-H.150S police face shield is shortened to make space for NBC gas mask cartridges and has a rubber seal at the helmet / shield connection to prevent liquid from seeping behind the shield. This item meets NIJ 0104.02 & MIL-V-43511C & NSN 4240-01-430-1983 specifications.
See other Paulson face shields here: http://www.paulsonmfg.com/products/tactical/Military-Police-Face-Shields