The middle flat ones. They are folded back some. I will have to check those shafts out good when we get the machines into the shop. We had a really wet start to the grass season with a lot of moisture in on the bottoms of the windrows. It doesn't help that everyone is going to larger windrows and cutting with rotary heads. The rotary heads have a tendency to rope up tight knots in the windrows in certain conditions, if you hit one with a stock impeller going to fast you were in trouble. With the Sunnybrooks could keep it moving through the machines. We plugged the APS a few times, and one main cylinder but no impellers. I ran the Cropflow set to the most sensitive setting, and I am a strong believer in that. It in conjunction with the Sunnybrook makes the combine an eating machine.