Yep, looks like a Charles 1st, a nice find. I spent a few afternoons there last year looking for buried treasure. Plenty of sinkers, musket balls, grape shot and 303 cases but no riches
I was told that the etrac is very good but very hard to learn so i gave it a miss and bought a Sovereign which i've since sold and now i'm saving for a new machine, don't know which yet.