● 4 keys ● DES/3DES encryption are optional ● Dust-proof and liquid-proof ● Can be cleaned with disinfection solution or other cleaning agent ● Specially designed to operate in harsh environments, making them ideal for web payphones, internet kiosks and other applications in public places. ● Vandal-proof ● Material: stainless steel ● Excellent tactile feel Mechanical Data ● Lettering: raised key with high density printing ink ● Life cycle: one million times per key ● Actuation force: 250g ● Key travel: 0.45mm ● Operating temperature: 0°C to + 45 °C ● Storage temperature: -30 °C to + 70 °C ● Size: 110 x 24 mm