I bought these as a last-ditch effort to avoid shelling out another $140 for duty boots that were in great shape except for a tear in the safety toe area.  For $20 bucks including shipping I figured "What the hell?" The pictures do not do the product justice.  I received the caps, reviewed the instructions and immediately set into prepping my boots.  Sanding of the safety cap is required.  Make sure you rough up the contact area with a purpose, otherwise the cap will not stick.  The epoxy is amazingly strong, and I had to perform zero trimming or "fitment" to my Dr. Martens safety toe boots.  In less than 24 hours I had the caps shined up with the boots and they looked more or less original (The leather caps are a duller, darker black dye than KIWI polish-a light sand job on the caps and a USMC shine job will fix them up).
The caps satisfied the uniform requirements and allowed me to keep my Doc's that are already broken in.  Excellent product and I recommend it.  Follow the instructions and you can't go wrong with this one.