The topeak race rocket mt pump is the fattest version in the racerocket series the all aluminium mountain pump gets big volume tyres up to pressure fast with an increased barrel diameter to push more air per stroke up to 90psi extendable hose takes the stress off the valve stem small size fits easily in your back pocket or if you want to attach to your bike frame the pump includes a side mount bracket with it being stylish in design it is a must have for your bike