I got the same "pinpointer" from kellyco with the exact same metal detector (delta 4000).
I used it for the first time last night. Two things I noticed. the pinpointer built into the delta 4000 is way more accurate with variable sound as you hover over the object. and the other is that the handheld "pinpointer" that came with the order seems very flimsy and easily breakable.
But obviously, you are using the "pinpointer" because you are on your knees digging up the object and do not want to stand up to hover over your dirt piles again to detect. But the problem I had with the "pinpointer" is that i would use the metal detector to pinpoint something 2 inches below the ground. Then I would wave the "pinpointer" over the exact same spot, and no tone. I would then dig out a clump of dirt with the spade (which is good quality from kellyco) and use the "pinpointer again". No sound. ok, I think I missed the dig spot with the pinpointer on the delta 4000. Ok, stand up, and wave the pinpointer on the delta 4000 over the hole I dug, no sound... now wave it over the clump of dirt, bing bing bing. Ok, back on hands and knees. wave the handheld "pinpointer" and no sound. ok, I break the clump of dirt into smaller pieces. Finally it picks up in one of the dirt clumps. But alas, I can actually visually see the penny now sticking out of one edge.
Ok, handheld "pinpointer" tells me that a visible coin is in the dirt clod I am holding in my hand. Not really helpful. Yeah, I guess I am with you... will need to find a new pinpointer that detects through more than .01 mm of dirt