New Version Now Available Shop Updated Saucony Zealot ISO 2 Here. Zealot: def. A runner who is fanatical and uncompromising in his/her pursuit of the ultimate running shoe. The all-new Zealot rounds out the ISO SERIES, offering runners PWRGRID+ and ISOFIT technologies in a lighter weight, lower-profile package. Two ounces lighter than the Triumph and built with a 4mm offset, runners will love how light, fast and highly cushioned this shoe feels.