... quality silicone watertightness ,acid and alkaline-proof ,high dustproof USB flexible keyboard: anti-pollution, watertightness, acid adn alkaline-proof, high dustproof ... printing technology auarantees the letter on the buttons of keyboard not to be worn away for a long time ... colors, the button bears to rype 2 million times.the keyboard is applicable to office ,hospital classroom, workshop, metwork bar ...