Quell is the maker of the EESeal FilterSeals brand of EMI Filters, Retrofit Inserts, and Transient Suppressors. EESeal FilterSeal EMI Filter Inserts are a simple, low-weight, small-size, instant-install, reliable alternative to filter connectors, filter adapters, and other types of interface and signal filters. You can easily retrofit or add an EESeal high-performance EMI Filter Insert to your connector in seconds, even in the field.