Well I din't know about puting the Platypus on an Excallibur, and yse I'm the one finding all the gold I have been posting on the Yank Assie forum, for minelab PI's. You can buy a waterproof connector kit, I have one and can change coils on mine, But they do not come with them, they come hard wired, headphones and coil deppening on what you buy, an 8 inch or the 10 inch coil. The lithim packs only apply to the minelab PI gold detectors, they are sold by DOC and only for the SD2000-3500's. The Excallibur comes with a rechargeable Nihb Pack, and run on 12 volts, as the PI's run on 6-7.5 volts. If you bought a new excallibur, I would go with the 10 inch coil, more coverage and when the waranty is up, you could think about puting a different coil on with the waterproof adapters. Until then the 10 inch will do you just fine, great depth and not to heavy. Grubstake