This item is the new Part Number H2418-99 to designate the size more effectively.

The old Part Number is Abatement Technologies H2520-99 OEM replacement HEPA filter for the following Abatement portable vacuums:

H2500 (serial #s 1155 and higher), H2500IV, H2500TF PPV

Abatement Technologies H2520-99 24 x 18 x 6  replacement HEPA filter has an extruded anodized aluminum. Efficiency rating: 99.97% @ .3 Microns, closed cell neoprene gasket on the downstream side.

Abatement recommends you change the H2520-99 HEPA filter after 9000 hours (1 year) of use under normal operating conditions.

This package ships with one filter.