This retro-fit speed sensor is an amplified device and offers clean signals back to the Micro Dash for steady speed and gear indications.  It features a tough fibre reinforced polyester design and a 6.0mm mounting hole.  The sensor needs to be directed at between 2 and 6 ferrous metal targets rotating on the rear wheel, either the sprocket nuts or the brake disc rivets are ideal, (stainless steel or aluminium nuts/rivets are not suitable).