I've owned several and the only one that has ever worked consistently is the FX. In addition to just working it has a nice interface with your smart phone.
SEE BELOW PRO CHRONO below it's a better brand than this one.
Found one maybe offer $40-$50max he had it relisted already. All you need is some cheap stick on lights to put on top of the white sunscreens to make it reliable under any lighting conditions.