There is no difference between the metal detectors. The HP indicates the type of package you’re purchasing the V3i detector with. This package includes the V3i, wireless SpectraSound headphones, 8x AA batteries, White’s Carry Bag, White’s baseball cap, and two battery packs. The battery packs are one rechargeable NiMH battery and a back-up AA battery pack. The HP package extras are the carry bag and baseball cap.