Gadget-loving nitrox divers and gas blenders who want a portable blending calculator can load their iPhones with the Nitrox Tools application. This software not only lets you plan your dives by calculating EAD, maximum depth and contingency depth for a given nitrox mix, but it also calculates your best mix for a desired depth and maximum oxygen partial pressure. And for nitrox blenders, the application includes calculators for getting the right mix whether you're blending with the top-up or bleed-down methods. Greg McLaughlin, a software engineer and instructor with PADI and TDI, based Nitrox Tools on the same formulas found in PADI's and TDI's gas blending manuals and nitrox dive tables. Planning calculations can be done in imperial or metric measurements, for fresh- or saltwater dives. Search "Nitrox Tools" on the iTunes store for the native app, $5.99, and take it on the boat with you. Don't have an iPhone? Visit moremobilesoftware.com for a less portable, but free, web-based version.