The REBEL Particle Pre Filter P3 is designed to offer high-level protection against harmful particulates when used with REBEL Gas Filter Cartridges LG-A1 and ABEK1. It effectively filters solid or liquid substances in a fine particulate state but must be used in conjunction with a gas filter and secured with the REBEL Particle Pre Filter Retainer (sold separately). This filter cannot be used on its own and should be replaced when breathing becomes difficult. Please refer to the spec sheet for detailed guidance and precautions.