Thanks. I tried using a disc magnet off amazon - Ceramic Disc Magnets, 0.472" Diameter, 0.197" Thick (Pack of 40) https://www.amazon.com/dp/B005HYDD1C/ref=cm_sw_r_cp_api_i_R8X8Eb81ZYB23

I haven’t mounted the monitor on the bike yet so I just took the sensor and passed the magnet close to it by Hand and it was only picking it up if it was nearly touching. Ended up ordering assaults magnet over their phone since it ain’t offered on the site