These are the poles I bought after much deliberation. Fixed-length walking sticks make sense for ultra marathons since you should be using them for the entire 100km and not having to stow them away. Telescopic and folding walking poles are great for packing away but will not be as strong as fixed-length poles with their joints – a bit like comparing a length of timber vs three pieces with joints. Carbon fibre poles are lighter than aluminium and weight really helps on ultra marathons. These walking poles are good value but you can always upgrade to Leki if you double your budget! Go get 'em!