Thing to remember, many of thee scumbags will try with bolt croppers and may not have an angle grinder; even if they do, it's unlikely they'll come tooled up with spare batteries and discs. Even the X1 will need 3 to 5 discs and likely a battery change, so any of these locks is better than not using one. Same goes for crop resistant D locks. I won't carry a lock that can be easily cropped, that's the minimum standard for me. Chains can all be ground through but larger ones cannot be cropped. It's a juggling act though and I don't travel with a heavy chain, as it's part of a layering system in combination of with several locks, so am happy with a 10mm Hiplok chain as it's still a visual deterrent and still needs time and effort to get through. Will thieves bother if you also have a grinder resistant lock and a disclock? Only the most determined or where they can lift a beke into a van. Any chain will slow them down and locking both wheels stops them wheeling it to a van....unless they lift the whole thing.