Amazingly bad design for 4 reasons:

1) NOT for today's fat skis. When a fat ski was 70mm at the waist, it was fine, as there was very little lateral torque that could be applied to the trekker-binding interface. Not the case now. With so much ski hanging off the side of the bindings, it applies enough torque to rotate the narrow trekkers right out of the binding. If you end up side-hilling up something over a couple degrees, which is pretty much anything other than a powder skin track across a flat field, you'll be hating life. They'll either pop out completely, or the ski will flatten out to the point that they start to slip down the hill sideways.

2) I have lost nearly every original bolt and nut on these, and that was when i had a screwdriver with me, checking as I hiked!! They didn't get the sizes, thread-counts, etc right on their hardware, and you end up needing to check them every quarter mile or so because they loosen constantly, even with red Loctite on them. It really makes for a bad day in the mountains when you and friends have to dig in the snow for a tiny screw just to be able to keep going.

3) Failure of the main pivot. When plastic gets cold, it gets more brittle. On a rather cold day (~10 deg F), I had the plastic toe piece that houses the main hinge pin shatter on me. It tripped me up and i fell over. Raging mad. Upon standing up on the other foot, that one broke too! Literally, 6" from each other, they both broke to the point of no hope of further use.

4) HEAVY!!! Like adding a 10lb sack of potatoes to each foot. You'll burn out MUCH faster with these than with a real pair of AT bindings.

If you are a person who likes to occasionally go about 200 meters outside a ski area boundary across perfectly flat terrain, then these are fine. But don't even think of getting them as a tool to access backcountry stuff, because they aren't. I've been going backcountry for over a decade now, and these are the worst product I have ever seen. Horrible design, and horrible craftsmanship. Save your money and get a pair of Fritschis or Dynafits.