Review on Enhanced Replacement Crankshaft: Advanced Compatibility & Polarized Design by Donald Phi

I have purchased three sets of sight glasses.1. Fits perfectly in the frame of Daniel Defense Gascan now resting on the seabed in Pensacola, Florida. RIP2. Bought a crankshaft frame kit. The mirror coating began peeling off the lenses shortly after installation into the frame.3. Another set for another petrol can. These lenses have too little edge. You don't want to stay in the frame. The optics are good, but the dimensional accuracy and quality of the mirror coating is questionable.