[gokyo]

http://www.ultradotusa.com/ultradot_dist_blue_009.htm

This would be perfect for a tri rail or any PS90 for that matter.

I bought one for my SLP Mark I

I may get one for my PS90 next.
If you then get this scope rail it would be sweet
http://mpftech.4gunlovers.com/

 

[ShipWreck]

That is pretty much the same optic as the J Point or Doctor Optic (I believe it is the same - just different brand names). Somewhere (maybe here on this site) someone stated that they tried it on their PS90. The problem is that they couldn't zero the thing. It's too high off the bore on a PS90, and the little optic doesn't have a wide range of adjustment. They stated that they had to use shims to make it work - No pic was posted, so I don't know exactly how it was done or how it looked.

 

[eBell]

I've got an UltraDot LT on my Tri Rail. No issues with zero at all. Weighs almost nothing, clear optics and easy to see dot in varying degree's of light.
No regrets so far. YMMV.

 

[Orbital]

how big is the dot?

 

[eBell]

Off the top of my head I'd say 4 MOA. Not able to check the packaging at this time.