Litelok claims that the X1 "resists angle grinder attacks" so I tested the claim. I'm using a mains powered grinder because that's all I have. You can see I'm not practiced with a grinder so it could likely have been faster. I only cut one side and wouldn't have been able to get the bike free but by the time I was done, the cutting wheel was toast. It's unlikely that a thief would have another wheel to swap on so I'd call this a success. Let me know if you agree.