the 250 needs a threshold, manual g.b. and an end to that terrible Bell Tone.Are you listening Charlie?? I have owned about six 250"s and alway sell due to the crumby Bong Bong Bong!!! That said , imho it is a far better detector than the F 70 I now use, the Omega 8000, F5 and others I have owned. I am not a newby, been at it since '76.. Now for the rebuttals. Ron