I have misplaced/lost a family heirloom and I am heartbroken. It's a treasured silver necklace with several "keys" on it. My Mother bought it in Denmark over 20 years ago. It's a very unusual piece of jewelry and my Mom loves it. She asked me to have it repaired for her and I brought it back to my apartment. I'm ashamed to admit it but I don't know where I put it after that. I have looked EVERYWHERE for it. The apartment is old and maybe it just fell somewhere in the cracks. I'd like to try and find it, please tell me what kind of metal detection device should I rent/purchase? Obviously, this would be for indoor use, please advise. I am a graduate student and don't have lots of money $$$ so please keep that in mind! Many thanks!