Extension tubes are an accessory for cameras with removable lenses. When inserted between the objective lens and the camera, the tubes move the lens away form the camera's detector which results in a closer minimum object distance. This also results in a reduction in image brightness. In addition, the objective lens will no longer focus at infinity.
The extension tube set consists of 6 tubes having lengths 0.5, 1.0, 5.0, 10.0, 20.0, and 40.0 mm. The longest four tubes have a male C-Mount filter thread on the camera side and female C-Mount filter thread on the lens side.