What do you want it for M8?
Best strobe i have tried so far in terms of cost / power is the Tectite 200.
but its big
The Jotron is damed expensive but smaller and as powerfull as the Tectite
The Xenec SL15 is much smaller hafe the price of the above but half the power too. 50m rated but i have had my ones down past 100 without issue.
Hear is my old OC rig with the Xenec in place.
I had it there for surface signaling asuming lost at sea at night.
ATB
Mark