Focus | BLS 400: Filters with universal RD40 connection
The BLS 400 universal connection filter series is designed to offer maximum protection and versatility, ensuring safety in a wide range of applications.
The BLS 400 series is a versatile and reliable solution for respiratory protection in professional environments. Thanks to the universal RD40 connection, the wide range of filters available and compatibility with various devices, these filters offer effective protection against a wide range of contaminants.
RD40 Universal Connection
BLS 400 filters are equipped with a standard RD40 threaded connection conforming to EN 148-1, making them compatible with many respiratory protective devices on the market. This standardisation ensures that the filters can be used with different masks, offering flexibility and ease of use.

Wide Range of Protection: A Solution for Every Need
The BLS 400 series offers a variety of filters for different protection needs:
- Dust Filters (P3 R): Effective protection against solid and liquid particulates, with a filtering efficiency of 99.99%.
- Gas Filters (A2, AX, K2, ABE2, ABEK2): Protection against organic and inorganic gases and vapours, ammonia and its derivatives, acid gases and sulphur dioxide.
- Combined Filters (A2P3 R, AXP3 NR, ABE2P3 R, ABEK1P3 R, ABEK2P3 R, ABEK2HgP3 R): Combined protection against particulates, gases and vapours, offering a complete solution for environments with mixed contaminants.
This variety allows users to select the most suitable filter for their specific operational needs, ensuring maximum safety at all times.
Filter Classification: Colours and Meanings
European standards EN 143 and EN 14387:2004+A1:2008 define protection against dust, gases and vapours by assigning specific identification colours to different types of contaminants. For example, filters for organic gases (type A) are marked brown, while those for inorganic gases (type B) are grey. This colour coding facilitates quick identification of the appropriate filter for each situation.

Class 2 Protection: Security at the Highest Levels
BLS 400 series filters are classified as Class 2, providing the highest level of protection against high concentrations of contaminants. This classification makes them particularly suitable for high-risk professional environments, where a reliable barrier against dust, gases and vapours is required. Choosing a Class 2 filter ensures not only safety, but also compliance with the most stringent standards for respiratory protection.
Compatibility with BLS Masks
BLS 400 series filters are designed for use with the following BLS full and half masks:
However, it is important to note that some filters weighing more than 300 grams may not be suitable for use with half-masks, as they may compromise comfort and fit. In such cases, use with full masks is recommended to ensure optimal performance.

Respiratory protection is crucial in many occupations, and the choice of the right filter can make the difference between safety and risk exposure.
Go to the BLS 400 product page to download the data sheets and find all the details you need.