This inexpensive tool is a must-have item for your stained glass workshop when working with lead came. It gently straightens your lead came. It is spring-loaded to hold your came in place as you pull your came to straighten it. Lead came should be stretched only until it is straight! Pulling too hard and "stretching" your lead came will take out the metal "temper" and narrow the channel. You don't want that! Secures to your work bench. Carded, but no instructions are provided.