High Efficiency Particulate Arresting is the expansion of HEPA, also called particle retention filter. Highly effective means particle catcher. Hepa filters are filters that can remove air up to 85% and particles up to 0.3 microns. Filters that are more sensitive than Hepa filters and 99.999% are called ULPA filters. Hepa and Ulpa filters have a paper-like structure consisting of special fibers that do not require maintenance. These filters must be replaced with new ones within a certain time period. Today, hepa and ulpa filters are used in operating rooms, hospitals and clean room applications due to their filtering performance, reliability and maintenance-free nature. Hepa and ulpa filters are available in MDF, plastic or metal frame models.