GM-100 is a stand-alone reader. It has a following specifications and features;

Specifications
▷ Power supply: DC12 ~ DC24V(Stand-by: 110mA)
▷ Frequency: 13.56Mhz
▷ Size: 150x50x40mm

Main features
▷ The capacity for cards & PINs is 7,000 cards & 100 PINs
▷ Classy design and water proof type
▷ Keypad is optimized for users and GM-100 is user-friendly.
▷ 4 ~ 15 digits
▷ Reading mode is Mifare card.