Widder Vest Differences The System vests have snaps at the shoulder blades where you can attach the arm chaps. The snaps are also electrical connections, and even without the chaps, you can attach the power cords for your gloves, so the gloves get power through the vest instead of plugging in separately. (I like this feature: fewer wires.) The System 1 has no collar; the System 2 has a heated wraparound zip-up collar. Ventura II has a heated collar and heated pockets. In the pictures on the web, the collar looks fuzzier than the System 2 collar. I can't tell if it tapers and doesn't zip all the way up the front, or if it's just folded down in the picture. The Mark II has no collar and no snaps for arm chaps. I think the Ventura II and Mark II have identical fits except for the collar, and the System 1 and System 2 are also probably the same as each other, but not the same as the Ventura II/Mark II. I own the System 1 without arm chaps: I got that one in case I decided to buy arm chaps later, and for the wiring convenience for the gloves. It fits me kind of funny: to zip it up, I have to stand tall and make myself skinny, as if it's too small. But despite that, when it's on, I have to slouch and bulk up my middle (the opposite of sucking in your gut) to get good vest-to-shirt surface area contact. I also have Gerbing socks. Pat Widder doesn't make socks, because he's not happy with the feeling of walking on wires when you get off the bike, and he hasn't found a suitable alternative. For me, on my half-faired bike, the socks make a HUGE difference in riding comfort, so walking on wires is worth it. -- Allan Pratt ==== also ==== I think the difference between the system I and system II is that the system I does not have a collar, and the system II does (or vice-versa). I have the system II model, with the collar, and I am very pleased with it, and highly recommend it. The inside of the collar is lined with a very soft material and it does not chafe - it provides excellent insulation for the neck during cold weather riding. The system I and system II models also accommodate the electric arm chaps, which I also have and also recommend. Cold weather dressing strategy changes a bit once you have the electric clothing. I just wear a cotton turtleneck, then the Widder vest, then my protective clothing. No more "layering" of clothing, which is great, because it eliminates the "overstuffed" feeling when riding. So, when you choose the size of your vest, choose it so that it will fit you appropriately with just a thin shirt on underneath it, not a sweater or heavy shirt or anything like that. The customer service from Widder is also first class, it is a pleasure to do business with them. By all means feel free to phone them if you have questions - the folks that answer the phone actually know what they are doing, they are not just "order-takers". Regards, Michael Moore Toronto, Canada STOC 2636