I use a make shift harness if I plan on swinging the 12" x 15" SEF coil on my F75. I use mine when hunting some fields, but mainly to go back over permissions that I had already gridded in 2 directions using the stock 9" x 11" DD. I dig darn near every repeatable signal, so that when I use the 15" coil, I can listen for the deeper targets. I