They seem to be 1.0 to 3.5...but lately I have been hitting a lot in the 4.0 to 6.5 range..maybe the reason I have finally hit some silver coins this month. But also I notice now that I have been digging deeper...it sure is a lot harder to get my weekly 100 coin day. Wanted it today...ran out of gas after 3 hours....did not feel even another hour would get it done...most I usually will hunt is 4 hours...but normally 3.