6061-T6 Aluminum Spacers and/or Pulley Step Spacers Our precision cut aluminum spacers and step spacers are perfect for replacing lost components from a previously purchased kit or for use in custom projects. Made in the USA from USA produced 6061-T6 aluminum. Length tolerance of +/- .010 Step spacers are made to mount an idler pulley. The length is for the larger diameter section height. The small section installs inside the pulleys bearing. Fits factory LS style ribbed and smooth pulleys.