The inner wall stays smooth because the solid brass can't rust or pit. As a result, the leathers last and last. Twin leathers for higher efficiency. Tough urethane facing on check valve. Rated for depths up to 3000 ft and temperatures up to 200°F (important if you're pumping from geothermal spring). However, for hand pumps, the maximum practical depth is 200 ft (with #442102, which 2" diameter). Pumping capacity up to 24 ounces per stroke (with #442103, which is 3" diameter, on a 10" stroke).
