This is a Double-Side PCB Circuit Board, Each PCB board has 28 pins.A side for pin pitch size 0.4mm, It can be used to convert QFN28 ( Body 4x4mm，Pitch 0.4mm ) to DIP-28 (2.54mm pin pitch)B side for pin pitch size 0.5mm, It can be used to convert QFN28 ( Body 5x5mm，Pitch 0.5mm ) to DIP-28 (2.54mm pin pitch)The PCB board mounting 2.54mm pitch Pin Header, It can be plugged directly into 2.54mm pitch PCB board, breadboard and 600mil width 28 pin DIP socket.Package content: 2pcs DIP Converter PCB BoardFor Detailed dimensions Please refer to below the picture.