Filtration systems for soldering applications are compromised of three filters. As fumes are collected, they first encounter the Pre-filter, which is a lower efficiency particle filter that is used to protect the primary filter from large particles, extending the life of the primary filter. Next is the Primary Particle Filter which is a particulate filter with large surface area having efficiency ratings of 85% and higher. A variety of filtration efficiencies are available to suit your needs. Lastly, a Gas Filter is included to eliminate any hazardous gasses that may be present. PACE's gas filters use high-grade activated carbon or they combine adsorptive and chemisorptive technologies to maximize effectiveness. To fully understand your gas filtration needs, always consult your Material Safety Data Sheet. The Arm-Evac 50, 105, 200 and 250 use "Combo Filters" which means that the Primary and Gas filters are contained in one filter cartridge. The Lab-Evac 100, Arm-Evac 500 and 1200 use separate Primary and Gas filters which need to be changed individually. Pre-filters should be inspected at least weekly. When they become clogged, they should be replaced immediately to maximize primary filter life. High Capacity Pre-filters must be used in combination with a High Capacity Filter. When filters need to be replaced, simply remove them from the Fume Extractor and replace with a new one. Disposal of used filters should always be done in compliance with local environmental regulations.