If you see a cheap GPX-4500 or a cheap GPX-5000 it might be a good idea to hold onto it, I have been very busy working away on some changes to the circuitry that makes a very big difference to depth, by careful component selection and additional active filters we can remove a lot more ground noise while cutting out the radio interference while increasing the input gain to get greater sensitivity and depth. More to come after Beta testing. The current upgrades allow you to get the relative same performance as a SDC2300 without the coil size and type restriction. Depths greater than the GPZ-7000 are obtained and also no coil size restriction.
