The compact SLK-77 features a full QWERTY keyboard layout, 12 function keys and red LED backlighting in a rugged ABS polycarbonate case measuring 9.25 inches by 3.85 inches (width-height). The durable keyboard has a keystroke endurance of greater than 10 million operations. The SLK-77 is NEMA 4X certified, with a completely sealed industrial silicone rubber keypad that can withstand the dirt, dust, water and corrosives that often exist in harsh environments. It also functions well in extreme temperatures, with a storage temperature range of -40°C to +90°C and an operating temperature range of -40 degrees C to +70 degrees C. The mobile version of the SLK-77, the SLK-77-M, features integrated mounting holes in the case. Both models are built with USB cables.