Competition shooters in-the-know intrinsically understand Co-Arc, and they have understood it for years.  But to the rest of us, what is it and why is it important??

In most simple term, Co-Arc describes matching all your optics with identical height-over bore.  Traditionally, when someone put an offset red dot on their rifle, the goal is to use it as back-up sights - and only deployed if/when the "primary" (12-o'clock) optic were to fail.  For that purpose, mount manufacturers engineer their offset mount to be super-low-profile, and tuck the red dot away minimizing intrusion to shooter's sight line.

But as time goes by, we noticed this approach really make your expensive red dot unusable... you have to bury your face into the cheekweld just to see the dot.  Transition from your 12-o'clock optic to your offset is slow and awkward, your speed and accuracy decreases, a lot of time just flat out waste of money on that expensive red dot.

So, what's the solution?  People started buying raisers and jerry-rigging to bring the offset red-dot back up to a "comfortable" height.  And with the advent of 1.93 (or even taller) optic, the holy-grail would be to ensure that no matter if you are shouldering your rifle for the 12-o'clock or offset optic, you maintain the exact same head/neck position and cheekweld.  This makes for a consistent and familiar shooting position no matter which optic you are using, and that is how our Rukh is born.  In fact, our Rukh is the first and only offset mount specifically designed from the groud up to complement taller (1.93+) 12-o'clock optics.

Long story short, we didn't invent Co-Arc.  We merely coined the term.  When you are shopping for offset mounts, especially to pair it up with a tall 12-o'clock optic, ask your supplier:  Will your offset mount Co-Arc??