As I have stated in some other posts... The 9v battery is not standard in size and can vary by at least 2mm
Garrett / ML Pro Find and a number of others will all suffer from Falsing due to the way the cables are fixed and attached to the cct board. Some may work better than others, but shocks and time will cause the problem to happen... The Deteknix X-pointer appears to be some what better, but only time will tell.
Just like computer HDD failures; it is a matter of when, not if.