I was running 9.5x5 Nokta coil, it was doing real well picking out signals in iron laden house sites, with decent depth on fringes but, coil seems to have grounded. Back to stock at moment. I've been looking at Nel or Magic coil for possible replacements. I snagged this rare killer snake button out of a very popular site with the small coil. I like the Anfibio, still learning though. I haven't had it very long. It's my kind of machine, sensitive, fast, chirpy, loud, & deep.