The thickest of these three chains resists bolt croppers and substantially slows down a disc cutter. It's the best chain we've ever taken tools to, and the thinner ones are pretty good too.
We tested three versions of chain from Pragmasis: the Protector 16mm chain with Squire SS65CS lock, the Protector 13mm chain with Squire SS50CS lock, and the 10mm chain by itself without lock.
All three were subject to our usual attack methods which include bolt croppers (concealable ones that thieves use, not ridiculous 6ft long versions) and a portable, battery-operated disc cutter.
The 16mm diameter chain is the best chain that we’ve ever tested, fending off the bolt croppers with ease, and taking in excess of two minutes with the disc cutter. The 13mm version was equally impressive, and even the 10mm chain could withstand our bolt croppers (although it could not withstand much larger bolt croppers).
Of the three chains we would choose the 16mm for shed/garage bike storing duties, and we’d plump for the short length of 13mm chain for portable (but still heavy at around 5kg) security. If lower weight is important, then the 10mm chain is still mighty impressive compared to almost all other sub 3kg chains on the market.