But these are a game changer! We knew there had to a better way for cookiers to fill their piping bags, and the Easy Fill Piping Bag Holder is it!
The diameter is perfect to hold each size bag. The height is purposefully chosen so that when your bag is placed in the holder and the tip is just touching the bottom, you can fill your bag to the top of the holder and this will give you the max amount of icing, and still enough room to tie off the bag. No more overfilling. 
The see thru opening is there for a reason too! First, so that you can see your icing as you fill your bag, and see if is has reached the bottom. Second, so that when you are ready to pull your bag out of the holder, you can reach in and hold the tip and your turn up the sides of the bag. No more getting icing on your fingertips or making a mess of the top of your bag! This opening also guarantees no one will steal your favorite bag filling "cup" to use as their water glass. ;) 
Hand wash only with warm water. Do NOT submerge in hot water. NOT dishwasher safe.