The rd1 had 7,000 hrs of battery life on setting 6. The new rd2 advertises 50,000 hrs of battery life at setting 6. I haven’t found any real reviews yet on the new one.
This Vortex Crossfire II 1x22mm 2 MOA Red Dot Sight will not fit that mount but the Vortex Sparc will. You can find it here:
https://www.opticsplanet.com/vortex-sparc-solar-2-moa-red-dot-sight.html
The Vortex Crossfire II 1x22mm 2 MOA Red Dot Sight could fit on a Ruger 22 LR Pistol like a Mark IV, if it has a picatinny rail to mount this optic. However, this may be a little large for a handgun. A Vortex Viper 1x24mm 6 MOA Red Dot Sight maybe a better choice.
Yes, the Vortex Crossfire II 1x22mm 2 MOA Red Dot Sight would be a good optic to put on an FNH PS90.
Yes, the Vortex Crossfire II 1x22 mm 2 MOA Reflex Red Dot Sight includes a low height mount which will fit picatinny flattop rails.
There are currently 3 variants - CF-RD2, which is the standard, red variant. The CF-GD2, which is the green variant, and CF-RD2-T, which is the red variant, with tan coating!
This unit has two night vision settings, allowing it to be used in conjunction with a night vision device!
Yes, the Vortex Crossfire II 1x22 mm 2 MOA Reflex Red Dot Sight will mount and function as intended paired with a shotgun.
This optic does not have a shake awake or an auto-off, as it is total manual control!
This optic will not fit the factory 3/8" grove atop the 94/22, however, if a weaver rail was installed, it will fit that nicely!