Act as an interpreter

Найбільш поширеним засобом захисту органів дихання у сухопутних військах США є протигази М40/М42. Від яких отруйних речовин вони забезпечують захист?

The M40 provides respiratory, eye, and face protection against chemical and biological agents.

Чи відомо Вам, з чого складається протигаз?

The mask consists of a silicone rubber face-piece with an in-turned peripheral faceseal and binocular rigid lens system.
A face-mounted canister (gas and aerosol filter) can be worn on either the left or the right cheek. Microphone, hose and canister carrier are provided for combat vehicle applications. The mask is furnished in small, medium, and large sizes.

Відомо що протигази М40/М42 зазнали деякої модернізації. Не могли б Ви детальніше розповісти,  які саме удосконалення були запроваджені?   

Several mask improvements have been introduced, which resulted in M40A1 and M42A1 configurations. The adopted initiatives included a quick-doff hood, second skin, canister interoperability (M42A1 only), and voice amplification (M7), new nosecup, two new carriers, and improved vision correction.

Одним з удосконалень Ви назвали додатковий зовнішній шар лицевої частини протигаза. Чи не могли б Ви пояснити більш детально?     

The second skin is a covering for the mask faceblank material that provides added agent resistance. The material used in the second skin is a butyl rubber blend which has excellent agent resistance and is very durable. The second skin is designed to be compatible with a quick-doff hood and future overgarment with integral hood. The quick-doff hood is easily removed during processing through decontamination lines.