This publication listed devices certified by NIOSH or by NIOSH and the Mine Safety and Health Administration. Types of items certified included coal mine dust personal sampler units, gas detector tube units, respiratory protective devices, self contained breathing apparatus, gas masks, supplied air respirators, respirators for dust, fumes, and mist, and chemical cartridge respirators. Names and addresses of distributors of the approved equipment were provided. The available test procedures were also listed. Sound level meter sets and their manufacturers were listed along with test procedures used for industrial sound level meter sets.