该SAE标准定义的材料是未增强的热塑性缩醛和热塑性6/6热稳定尼龙，因为这两种材料都将在该应用中发挥作用。 选择的具体材料将取决于最终应用的环境和热量要求。它们用于液压制动系统的真空助力止回阀。

The materials defined by this SAE Standard are unreinforced thermoplastic acetal and thermoplastic 6/6 heat stabilized nylon, as both materials will function in this application. The specific material chosen will depend on the final application's surroundings and heat requirements. They are for use in vacuum booster check valves for hydraulic brake systems.