used a few in the past omm and cheaper decathlon versions.best one in current use is the innov8 race ultra theres a 5 or 10 ltr . incredibly comfortable .cant recommend enough .its on sale if you shop about .
Loved it !!! It's 2 yrs since I've done a half marathon on Tarmac .( prefer mud and peat bogs ) but I signed up to help a mate out who is training for a spring marathon , and this was on the training plan . Loved the route , didn't notice any bad ups , just loved all the downhills . My mate got a pb ! Nice to have route closed to traffic . Lovely marshals . I'll be back deffo next year !