good evening and happy passover/easter! session level will be determined by your skins requirements. another incredible thing about this product is that it can use in an open or closed position according to the convenience. order your copy of twisted today! when will they be back in stock. do give us a call, we would be delighted to serve you. update: under agreement in ~30 days! be sure to keep this in mind when you are using this. actually if you have some good idea for their class name, please, don't hesitate to share it. owners are very friendly and hardworking. 