FOR CANON EOS-R Mirrorless Cameras: This metal auto focus macro extension tube adapter ring is specially designed for EOS-RF mount(Not suitable for other cameras) | MACRO MAGNIFICATION: Macro extension tube can be used alone or in superimposed, when using the extension tubes alone 13mm or 18mm or combination 13mm+18mm=31mm; Extension tubes are designed to enable a lens to focus closer than its normal set minimum focusing distance | AUTOFOCUS: When using a macro extension tube, it is recommended to use the manual mode to change the shutter speed directly to control the exposure level; While using 2 rings together, we suggest you to use manual focus or Increase the lens focal lengths for it's a little bit difficult to auto-focus with 2 rings together, and also can protecting your lens | IMAGE QUALITY: Its no-glass design minimizes potential image quality loss and provides consistent quality for your shoots, will not affect the quality of the shooting screen | NOT EASY TO BREAK: The outside of the ring uses a frosted spray layer close to the lens, aluminum mount, no deformation, high temperature resistance, strong and durable; All copper electronic contacts, can connect the camera and lens