I personally don't see the advantage of a 8-9" coil...other then being a compromise between a larger or smaller coil. If one is a deep coin hunter 8-9" and in most cases even , 10" coils, will not afford one the necessary depth for deep coin hunting. And I know for a fact there some good old coins deeper then 8". And, for trashy spots, 8-10" coil sizes are to big. Personally, I would be pretty happy with a 12" coil as my stock coil and a 5-6" size for trash laden spots. And here again, I know for a fact there are many good masked coins, too. But, to each his own. HH jim tn