3 bag fibre glass bubble bead filter. We are BIG fans of these filters because of the superior backwash ability that comes with the blower. The advantages over a sandfilter are ease of maintenance as the blower does all the heavy lifting for you with masses more agitation of the bead bed than a a sandfilter can ever hope to achieve. The plastic media (included) should never need replacement and the filter can achieve a measure of bio filtration as an added bonus. Comes with blower attached.