Information: It is made in plastic with light weight. Automatic Extension Tube Set is combined of 2 rings - 10mm, 16mm. Equipped with electronic contacts which transfer exposure data . Made of ABS plastic. All automatic functions work well and there is no need to set them manually. As for AF engine and TTL auto exposure in modern lenses there is no need to worry, it works perfectly well with extension rings. Use these by inserting between the lens and the body of SLR cameras. Compatible With: Canon EOS M mirrorless lens digital camera Kindly Note: 1) When using extension tubes the lens will not focus to infinity. The focus range will be greatly limited to a very close focusing distance. 2) There is light fall off when using any extension tube, sometimes the equivalent of 3 f-stops of light is lost when using multiple extension tubes together. This light lost can affect the camera"s ability to auto focus. Manual focusing is recommended should the lens begin to "hunt" (not lock onto the subject).