4400 Series Miniature EMI Filters Tusonix Miniature 4400 Series Miniature EMI Filters are ideal for applications where small size and high performance are critical and a threaded mounting technique is desired. The C and L configured EMI filters are available in two physical configurations and can be supplied with either unified or metric thread. The small package and large range of electrical characteristics of the Tusonix Miniature EMI Filters 4400 series make them an effective solution for a variety of microwave applications.