A common problem with the old Edison phonograph 4 minute Blue Amberol cylinders is the expanding and distorting of the plaster inside so they won't fit the phonograph mandrel properly. Fitted with a strip of high quality- very long lasting abrasive,this tool is properly tapered to go inside the cylinder and ream the inside of the cylinder so it will fit the phonograph mandrel again.The last 2 photos show a cylinder in need of reaming (before) - and then how it fits the mandrel after being reamed.This reamer is a quality - well made tool- no need to change the abrasive, it will last for years.Join the thousands of my satisfied customers - worldwide. Makes a fine gift for that phonograph enthusiast. Please see the photos.Reamer may look slightly different than pictured. Thanks for looking! Check out my other items!