The FMK-04 model Material: aluminum alloy + plastic; battery capacity: 180mAh, 2mA/3.7V Broadcom chips 3.0 A total of 81 keys Two hours for charging; eighty hours for working; two months for standby Size of unit: 35.8*10*0.9 cm Size when folded: 17.8*10*1.8 cm Weight net: 208g Space gray is the color.