These Spiral Tilt Balances by Make-2-Fit are constructed of steel and come in a mill-finished tube. The FL series measures 3/8 inch in diameter and feature an identifying red-colored nylon bushing. The bushing colors of spiral tilt balances indicate their spring weight, and the red colored bushing designates these balances are for use with sash of medium weight. These spiral balances are used on vinyl single hung tilt windows, and they are easy to install with a few simple tools.