Drager 6738856 RD 40 – K2 Filter In all kinds of industrial applications, whether in the chemical industry, automotive, shipbuilding or metal industry, Drager X-plore Rd40 Connected Filters are widely used in combination with masks. While providing protection against substances that threaten human health, it provides high performance and ease of use with low breathing resistance. General Specifications Product Code: 6738856 Filter Code: K2 Connection Feature: Rd40 (screw) Filter Type: Gas Filters Airtightly packaged Substances Protected: Ammonia Compliance Norm: EN 14387:2004 + A1:2008 / CE approved Compatible Mask.