This model is neither the Lite nor the QuickLace. What it is, is sturdy, rugged-soled, waterproof, breathable, kneehigh delight! So comfy I fell asleep wearing mine the first time - in the house! Out on the water it's very flexible on the footpegs with a great outer sole to keep you off the muck as you enter and exit. There is a buckle at top for a great fit just below the knee. This mukkluk is sized best for slender to medium thick calves. After four hours of paddling my feet stayed warm but not too warm wearing Capilene/wool/nylon socks. There is plenty of room to layer socks as well.
This is labelled a Men's 6 (Woman's 5). I have size 5.5 feet so this feels maybe a half size larger, but it does leave room for different configurations of underlayers. Am completely satisfied. The MK100 is apparently an older now discontinued model, and can be found as new/old stock. I found mine, new, in box, at less than half the MSRP of a pair of new Quicklaces.