Abus Phantom cable lock
It's made in Germany, which, for a lock, sounds good right off the bat. It's made by ABUS, a famous German lock maker and, as a matter of fact, the inventor of the U-lock (not, it wasn't Kryptonite or Citadel).
Mr. Phantom is a key-lock (comes with two keys) has a thick cable covered with hardened steel scales covered by rubber. It's a thick and twistable/compactable lock that can fend off anything short of a bolt cutter.
It comes with a mounting bracket that fits almost any round main-frame tube on a halfway normal bike, but you can twist and fold it down to a 7-inch diameter double-loop and throw it in a bag or basket. Put a loop of cord around the key and put the lock thru that. Or on a short trip when you're super lazy, wear it around your neck.
It's 10x easier to use than a U-lock, fits around things way better, and there's no fussing with which end of the shackle to put in which hole. It's a good choice for a downtown daytime lock, assuming you're not parking the bike for a long time in a gritty area.
There are probably two hundred good locks out there. Each has its trade-offs, and you can make a case for any of them, but this is the one many of us use every day. Easy and good!
Weight without bracket: 23.2 ounces.
With bracket: 25.6 ounces.
Comes with two keys and one frame mounted bracket.
Length: 3 ft 7 inches (110 cm)
Millennioflex Phantom 8960 Steel-o-Flex is the official Abus name for this particular cablelock.
Go to lockitt.com to order replacement keys.