I bought this to secure the bikes in my shed, it's reasonably easy to instal (if you have a good drill and bit).
I've seen it reviewed as one of the strongest and most secure ground anchors on the market, and I agree completely.
It is attached to the floor with 4 rawlbolts with allen key heads, these then have ball bearings installed in them to prevent them being undone and then plugs are hammered in to completely seal the whole thing.
There is room for 2 or 3 security chains or locks to fit through it.
When a good lock and chain is used with it I can't imagine how anyone could defeat this, just make sure you instal it where it will never need to be moved.