Puma EXPLORE NITRO MID GTX The Puma EXPLORE NITRO MID GTX men’s hiking shoes are built for all types of trails, from flat and gravel to steep and rocky. The combination of NITRO foam and PROFOAMLITE in the midsole maximizes comfort on any terrain. The distinctive collar shape, combined with the integrated lacing system that supports the heel, makes these shoes an excellent companion on trails. They have a water resistant GORE-TEX upper that allows you to explore trails. Puma EXPLORE NITRO MID GTX