P921 is an ABEK type class 1 filter that provides protection against:

• Organic and inorganic acid gases and vapours
• Sulphur dioxide
• Ammonia and its derivatives (boiling point higher than 65°C)

The special Portwest bayonet system ensures a safer connection between the mask and the filter, while the twin filters offer:

• Improved comfort
• Better balance

This filter is compatible with the following masks:

• P500 Full Face masks
• P420 Half Masks
• P430 Half Masks
• P421 Half Masks
• P431 Half Masks