The largest of the Echomax range, made from 3mm glass fibre for large yachts, work boats and commercial fishing craft. The EM 305 model has been successfully tested by QinetiQ to ISO 8729, SHIPS WHEEL MARK, SOLAS, RORC and ORC and meets sections A.1/1.33 and A.1/4.39 of annex A1 of Marine Directive 98/95/EC. Recent tests by the MCA recorded peaks in excess of 70m². Mast or deck bracket mounting. Not suitable for free suspension.

Following a years trial by the US Navy Submarine Division the EM 305 has been chosen to give added radar visibility upon surfacing.