Cinnemon,
Sorry I'm so late in getting back to you. The Quickfit System of exercise machines are based on hydraulics, no weights to change. The resistance created by the hydraulics causes you to push or pull the machine as hard as you want to. The harder you push or pull, the harder you work out. You are not lifting weights, but raising or lowering the equipment against resistance. I'm not an expert on the machines, but I do know they generally work both sides of a muscle at the same time, therefore there is no soreness the next day. That was what surprised me the most when I started there. There are 12 machines in the set. Some work upper body, some lower body, some the abdomial area. I found some various web sites that show you the machines, & I don't know how to insert "links", so here are the sites:
www.get-fit-quick.com/quickfit_circuit.htm
www.areaclicks.com/curvesEA/
www.curveswestlake.com/quickfit_circuit
The best way to see what they do is to visit a Curves. They'd be happy to let you watch the ladies work out a while, and talk to the members to see what they have to say about the machines. Some Curves even let you try a machine or two--you'd have to ask. Hope I've been of some help.