Here is one from another brand Al max that has the same diameter 19mm (mine is from pragmasis also a 19mm in reality though it is 19.85mm minimum by spec) with the same padlock that i have a 16mm abloy.
I had the mul-t-lock 18mm but i sent it back because the key was weak and would have break eventually. And i would have had a hard time cutting a lock-chain this size due to a broken key stucked inside the padlock. If they had an abloy 19mm or a mul-t-lock key without the plastic part i would have gone for it instead.

I have some doubt regarding the resistance of the mul-t-lock to liquid nitrogen attacks, the abloy is resistant to this attack as shown here at 3m30:
http://www.youtube.com/watch?v=Yh46F3we1-M

Ideally, a sargent n greenleaf 951C padlock would be ideal but the price just doesn't make any sense so I had to compromise
https://securitysnobs.com/Sargent-Gr...1-Padlock.html

The combo padlock-chain is not cheap but i will probably have this chain all my life, the padlock will get stucked eventually one day so that i will probably have to cut it.

Regarding the weight of the chain it is about the weight of a bicycle for each meter length 6.3kg/m or 4.23lb/ft, hopefully 1m/3.28ft long is not so heavy ideally 1.2m/3.94ft would have been perfect. With a 1.2m long chain you can attach to most things without giving slack that a thief can use.

Since the extra weight on my bike is noticeable mostly when climbing to compensate i had to reduce the chainring size.

Also, because of the size of the chain i had to remove one spoke in order for the chain to go through the bicycle wheel. Haven't had any problem with it since the removal a few years back.