The 65” brake line is used for the Honda Grom dual-caliper handbrake, which runs from the master cylinder on the left handlebar to the second (dedicated) caliper on the rear rotor.
If you have a Honda Grom with a dual-fitting (junction valve adapter), you will need the shorter 42” brake line. This is also known as a single caliper setup.
Regarding sport bikes, you will need a 56" brake line is used for single caliper (dual-fitting) handbrake kits for street bikes.
If you have a dual caliper setup on a street bike, you'll need the 80" brake line.