I have a Vortex Viper on a Gen5 Glock 34. The co-witness sight aligns perfectly. What I did not realize is now half of my sight below the dot is gone and blocked, so it's important to keep both eyes open. Sight comes with everything you need to put it on, awesome! You will need to order a new holster because the front sight is tall, around .5". Other than that, it's an excellent product.