EX: Letter J ; if you switch NUMLOCK ON and when you click letter "J", it will input the “1”. Keyboard Size: 28.5cm x 12.6cm x 2.2cm Packaging Size: 30cm x 14cm x 3cm Ultra thin and chiclet keyboard USB type, Plug and Play With sound off key Mini type and full-function Fully compatible for PC and laptops Button up to twenty million times long on life Best for business office and home Antistatic, anti electromagnetic interference Easy to operate, leading fashion design Low noise, comfortable feel High life granular silica gel, the service life of 10 million times more Even by the FCC CE and other certification