All Louet wheels feature a smooth ball bearing operation, easy treadling, and a well balanced wheel. They are easy to use and feature low maintenance. The orifice on the standard wheel is a sufficiently large 1/2 inch as are the bobbins which hold approximately 4-6 ounces. This will allow you to make novelty as well as fine yarns. All wheels also come equiped with a hand attached 2 bobbin lazy kate. Technically all models (except the S45) are the same. Each wheel has a single belt bobbin drive with an adjustable flyer brake to regulate tension. The flexible belts are made of polyurethane and never need to be adjusted. All bobbines have three settings that can be used to obtain three different spinning speeds. The ratios for all wheels (except the S45) are 1:5.5 for slow spinning and heavy yarn, 1:7.5 for medium yarns, and 1:10.5 for fast and fine spinning. All wheels, except the kit wheel S17, come modestly unassembled. They are easy to put together with the tightening of just a couple bolts (tools included). I've put them together myself. In about 5-10 minutes, you're ready to spin. The Louet wheels come with a 10% discount off MSRP and free shipping!