R99

词形变化

R99s 复数

释义与例句

n.
  1. 1.

    R99; Ellipsis of NIOSH R99.

    R99 standard

    不可数 可数
  2. 2.

    R99; Ellipsis of NIOSH R99.

    R99 filter

    可数 不可数

词源

From Initialism of Resistant to oil particles with 99% filtration efficiency in NIOSH air filtration ratings.

来源：wiktionary