Got curious and looked. Go to http://www.choketube.com/, click on wrenches in the left column, and you will see a 20 guage wrench for $17.95. This isn't the brand I have, but it is the type I use, and works great. This is what I am going to get for my RBL. Once you use a wrench of this type, you won't use anything else. No more pushing to seat or having to go slow to keep the teeth engaged in the notches.