Make your Optical Tooling scales more flexible with our Invar scale extension kits and accessories. Use our Invar kits to extend the length of your scale in various customizable increments. They are constructed from Invar, which is a high-nickel alloy of steel having a greatly reduced coefficient of thermal expansion. Their length changes only a small fraction of the amount that “normal” steel changes with temperature variations. We have a number of accessories too, including rotating scale holders, tooling ball adapters, target holders, square feet to keep the Invar tubes from rolling around, and more.