Where can I get a manual for a BH VLF-SPD / RBS Discriminator which I was just given. It has two batteries. A & B, which both take a 9V connector but one is a 8AA pack. Which?? I have used detectors before so can probably figure out the rest, but would prefer the official word. Would appreciate a copy, email or snail mail is fine. Will pay reasonable fee. Thanks...Will