The Yukon Ab Crunch Machine is one of the best ab crunch  machines I’ve ever had the pleasure to work out on. It sells for just over 300.00 and all parts are warrantied for life.
It’s actually quite simple to use and will work both upper and lower abs. The seat is adjustable for people of varying heights. You sit upright and grab 2 bars positioned on either side of your head. Then, you crunch at the pelvis in a forward movement using only your stomach muscles to do this. Your feet are locked in under two foam pads at the bottom of the crunch machine. Make sure your elbows are facing forward.
To increase resistance, you can add weights to a vertical bar behind the back pad. You lean forward approx 10 to 12 inches, no more. This will work what is called the six pack. From the navel to the rib cage. I suggest doing a set to failure, till you can’t do another rep and the muscles in the stomach are sore. The abs should be worked prior to any workout with weights.
To work the lower abs, from the navel to the groin, you can do leg raises. Adjust the way you sit on the seat by positioning yourself to the edge of the seat. Lean back on the back pad and raise your knees above parallel to the floor. Squeeze at the top for a few seconds then straighten the legs out. Do as many as you can to failure. Again, this exercise should be done every time you work out.
The movement on this machine is exquisite. It suits every one and is very easy to use. I’ve sold it to a few light commercial gyms as well.

The Yukon Ab Crunch Machine is money well spent because it’s a piece that can be used almost every day and will last for years with virtually no wear and tear on it. It’s a must to own in any home gym.