When juicing vegetables (for example wheatgrass, etc.) it is easy to overload a juicer. All Angel juicers will automatically stop in this instance. However, the 7500 and 8500 will also automatically reverse the motor to free the jam. In the 5500 this is done manually. This will prevent too much pressure from building up in the machine which could possibly damage the juicing screen. The 5500 and 7500 are made from SUS304 food-grade stainless steel. The 8500 is made from SUS316 surgical-grade stainless steel.