Thank you for viewing this item. I opened it after purchase and set it up in a cage, but it was too big, so I didn't use it and have been storing it at home. (The box has some minor stains.) A 25cm silent running wheel, designed for peace of mind with a pairing system. - Brand: SANKO - Product Name: Silent Wheel 25 - Size: 25cm - Features: Pairing system, silent design - Instruction Manual: Included Please understand that this is a used item.