I goofed when I bought my first Flatliner and bought a right hand unit. I took it completely apart in an attempt to swap sides and found that it can't be done due to the locking cam and elevator gears/teeth. The optic part is installed and then melted into a bead so it wont pull out of the housing. I used a nail clipper and neatly clipped the bead off to remove it. Once I found out that I was going to have to return it...I heated my soldering iron and just tapped the tip and formed the same bead. I have always felt this saying was very true...It isn't yours until you have taken it apart and put it back together again.