“Having recently purchased rear bottle holders for the first time, unaware of their built-in ejector mechanism, I can vouch for the sturdiness of these bottles! Despite some ejections at speed, only one has broken - all of the rest have survived to fight another day! I bought this size for the first time as they are the size for which all of the sachets are measured. Also saves a bit of weight during an IM if I carry two of these instead. Great functionality and very durable.”