Discussion
wjwren said:
what is a cylinder guard?
This is a cylinder guard. You can retro-fit a cylinder guard to most doors that have a euro cylinder lock, in order to resist some destructive entry methods like lock snapping. 
Googling 'euro cylinder guard' should turn up a few different types of guard (e.g. UAP, Fullex). Different guards fit different doors more easily. Hence it's worth first removing your door handles - to see which guard looks easiest to fit your particular door - before you buy. YouTube doubtless has an instructional video about how to fit a cylinder guard. It's fairly simple DIY.
My understanding is that cylinder guards were designed and fitted before anti-snap cylinders, our doors were already fitted when we moved in (around 8 years ago we think) and already had one fitted. I replaced the cylinder with an anti-snap anyway, but apparently it was the cylinder guard that has stopped them getting in.
Gassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff