Same as Rocker I've used a couple of Optimate's for years.
It's worth noting that they are not plug in and forget.
Depending on result of the charge indicated by the LED's the instructions state to disconnect for 12 hours and start the process over again.
Case in point, my 2016 CB500F on original battery got a bit low over winter, after charging on the optimate LED 6 was flashing, normally would be static when fully charged, disconnected for at least 12 hours and started again, this time LED 6 was static and battery all good.