Having spent much time trying to stop my saddle moving from a bike purchased in France I was finally told by a bike specialist that the fitting was wrong. New seat post has solved he issue instantly. Only regret is that original bike sold by Decathlon Albertville had faulty seat post fitting.
Decent enough. Replacement for seat post that was too short on dual suspension MTB. Could have bought a super light one, but far more expensive.
reasonable price, light weight