The Topeak Mountain DA mini pump is a high volume bike pump for mountain bike and fatbike tyres. Dual-Action The Topeak Mountain DA features the Dual-Action system. This system features a special valve, which pumps up to 2x more volume per pump stroke. As a result, your tire will be inflated in no time. Sturdy design With a maximum pump pressure of up to 4 bar (60 psi), this bike pump is specifically designed for use on mountain, city and fat bike tires. The thumb switch ensures an airtight connection to the valve. This ensures no air pressure is wasted during inflation. The pump head is equipped with a dust cap to prevent the pump head from getting clogged with spraying sand and dirt. This significantly extends the life of your mini pump. Especially during intensive use in wet forest environments.