Cassette Housings

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Air Sampling Filter Cassette Housings

Zefon International carries a wide range of air sampling filter cassette housings. Purchasing only the filter cassette housing is different from our pre-loaded cassettes in that they lack a filter media and are unassembled. These housings are intended for customers who want to assemble their own filter cassettes. This provides customers the ability to purchase any type of filter membrane they wish to use, and pre-treat, weigh or perform any other type of pre-assembly step they wish. We manufacture these housings to an incredibly high standard of quality, performing rigorous testing to prevent leaks and other defects. The result is a product you can trust in the most demanding applications.

Browse our inventory online and visit individual product pages for detailed specifications.


Material Options

We offer our replacement sampling cassette housings in six materials:


  • Clear styrene:

    Clear styrene is our most popular material option. Because it is clear, it provides excellent visibility into the housing, allowing you to confirm visually that the filter media is installed and working correctly.

buy styrene cassette housing

  • SAN:

    Very similar to clear styrene, SAN is slightly more durable. This material is recommended for use on 37mm 4-Piece configurations to provide stronger support with the extra spacer ring.

buy san cassette housing

  • Opaque styrene:

    We manufacture our opaque styrene housings from the same durable material as our clear products. However, opaque housings feature a dark brown tint that prevents light transmission. This is useful if the contaminant being collected is affected by light.

opaque housing

  • Polypropylene:

    Polypropylene housings are solvent-resistant for use with a variety of chemicals. They have a milky, cloudy color that offers limited interior visibility.


polypropylene housing

  • Tenite:

    TeniteTM is a brand of plastic manufactured by Eastman Kodak that is well known for its chemical resistance. Zefon manufactures 37mm 2-Piece housings out of Tenite specifically for use in fuel monitoring. This material resists fuel from chemically attacking the housing and is suitable for many grades of fuels, including aviation fuels.


  • Conductive black polypropylene:

    Finally, our conductive black polypropylene housings feature a carbon filling that makes them electrically conductive when grounded.

conductive black housing


Design Options

Material construction isn't the only deciding factor when choosing a replacement cassette housing. We offer several designs for different applications and tasks, including:


  • Two-piece standard-style housings:

    Two-piece standard-style housings have 35% less surface area than a three-piece cassette. As a result, they work best in closed face sampling applications, where it is advantageous to minimize the amount of contaminant that clings to the wall of the housing via electrostatic force.

2 piece housings

  • Three-piece standard-style housings:

    Three-piece housings feature an additional ring, usually ½” in length, separating the inlet from the filter media. They offer improved flexibility over two-piece models as they are suitable for both open and closed face sampling applications, and compatible with aluminum cyclones which connect to the spacer ring. However, as noted above, more surface areas mean greater electrostatic force, so less contaminant gets to the filter membrane.

3 piece housings

  • Four-piece standard-style housings: 

    Four-piece housings feature an additional two rings, usually ½” in length, separating the inlet from the filter media. They offer improved flexibility over two-piece models as they are suitable for both open and closed face sampling applications, and compatible with aluminum cyclones which connect to the spacer ring. The four-piece allows for a center filter placement to meet certain European standards and for the shoot-through FTIR cassette.

4 piece housings

  • Asbestos-style cassettes:

    The asbestos style cassettes get this name due to their unique shape of the cassette outlet, sometimes referred to as a “bell” shape and with the most popular use for this design is sampling for asbestos, hence the name “asbestos style”. Most asbestos sampling uses a 3-Piece design with a 2” long spacer ring which is known as a cowl due to its length. Other configurations are available including 2-Piece and models with a ½” spacer ring.


Closed face sampling involves keeping the inlet in place and removing all plugs on the cassette, whereas open face sampling involves using a three-piece housing and removing the inlet component. For more information about the potential applications of each technique and each housing style, please contact Zefon International to speak with one of our knowledgeable representatives directly.


Quality You Can Count On

Environmental technicians and air quality professionals can appreciate the value of consistent, repeatable processes. Consistency is one of the main characteristics of an ISO 9001:2015-certified management system — and a key part of how we can offer high-quality products at an affordable price.

All Zefon International air sampling filter cassette housings deliver the performance you can count on. Shop online, call one of our highly trained sales representatives or contact a dealer near you.

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