1 , office chairs, English officechair, narrow definition refers to the person sitting at the desktop in the state sitting chairs, broadly defined as chair for all offices , including staff chairs, conference chairs , guest chairs, training chairs. 1 , office chairs : for indoor use single seats . 2 , swivel chair : the seat surface can be horizontally rotatable office chair . 3 , according to the classification office chair adjustment method : a) type Ⅰ: seat and back are adjustable office chair ; Ⅱ: only seatback angle adjustable office chair ; not adjustable office chair : back , seat , armrest the relative position and angle are not adjustable office chair .