Bought this pump originally intending to carry it in a bag on my mountain bike. As it happens it fits perfectly on bottle bosses. I have two on my bike, so no problems carrying water and the pump. I did buy a smaller pump, but it was the screw-in type and it used to unscrew the valve and deflate the tyre after spending ages pumping it up. This pump simply pushes in and just does the job. I bought the one without the pressure gauge as I have a big foot pump at home and this is simply for punctures out on the road. Does the job, nice and chunky and easy to use. Perfect.