Audit Neutral Density Filters
Available from Environmental Monitor Service
Environmental Monitor Service, Inc. manufactures quality, precision neutral density filters for use in all of the most popular Opacity Monitors. Used for EPA audits and service, our filters are NIST traceable and fully certified. EMS filters are manufactured with high quality optical substrate material, flatness of 3 to 5l per inch and parallelism of 3 arc minutes or better. Each filter is serial numbered and comes with its own scanned trace which is dated and signed. The filters are labeled with the value in both Optical Density and Opacity.
Along with manufacturing our own neutral density filters, EMS can recertify any competitor’s model. Our filter certification service sets the standard in the industry for speed and cost, call us today for details.