Note:This product is suitable for most kinds of navigation DVD volume knob,this isn't the normal knob,please verify the dimensions Appearance: The hih-grade atetial shell is madeof aluminium alloy and digital grinding; Size:26x13mm; 23x13mm; 20x13mm Inner Hole: D/Half Axis Shaft & Plum Axis Shaft; Inner Hole Diameter:6MM; 2pcs/lot