Race face ambush knee d3o guardthe ambushs open back construction means no awkward shoe removal on the trail featuring d30 high performance shock absorbing foam features open back construction means no awkward shoe removal on the trail featuring d30 high performance shock absorbing foam d30 high performance shock absorbing foam perforated neoprene enhances venting and moisture control terry lined for wicking and comfort open back construction no shoe removal necessary foam padded si