I purchased a "Duo" for my Gran who was having difficulty holding an ordinary cup and was constantly worried about spilling the hot contents on herself. As we quite often visit relatives or go out for meals and call in at coffee shops, I didn't want to have to take a two handled cup with me everywhere the "Duo" was an ideal alternative, I can just push it into my handbag, it's light and easy to carry about and it saves me having to worry about transferring hot liquid form one cup to another. I just pop it onto the side of almost any size cup or glass and my Gran feels much more confident about holding a drink and not worrying about spilling it.