I could be wrong, but I'm pretty sure the Lazer 2 only comes in equal sizes, ie, 20" 22" 24" to suit your motor as
you need to use whats known as a small hub!
The odd numbers are Lge hub for 135hp+
Merc, Mariner and Honda splines are all identical, Honda used to use a merc lower unit, may still do.
If you are currently running a 19" ally, I would try a 20" Lazer. Beaulieau is a good source for props, don't pay anymore than £100.00 for a good en.
Part no for a 20" Lazer 2 small hub is: 48-16990A46
It is better to remain silent and be thought a fool, than to speak and remove all doubt!