The PM1200 Air Filtration System traps up to 99% of all 5-micron particles and 85% of all 1-micron particles for a healthier work environment. Three blower speeds modify air flow. The unit can be operated either at the cabinet or with the remote transmitter which uses radio frequency eliminating the need for line-of-sight operation. The timer has nine settings allowing continuous operation for up to nine hours while you re away and will shut off at the end of that period. The filter guards can be removed and installed without tools for instant filter access.