3M™ Secure Click™ Hard Case P100 Particulate Filter D9093CB, with Nuisance Level Acid Gas Relief, 144. NIOSH approved for use with 3M™ Secure Click™ Respirators in environments containing certain oil and non-oil based particles. 99.97% filter efficiency meets NIOSH P100 test criteria. Use with 3M™ Secure Click™ Respirators. Hard case recommended for harsh environments with a need for easy decontamination and protection. Hard case helps protect against sparks and high heat.