product manual:
 
1, change the caliber adapter ring, can be installed to the front of the lens to achieve the same aperture of the same aperture filters, hood, additional lenses and other accessories or to achieve the purpose of the lens diameter.
 
2, the transfer ring is made of aluminum alloy, black, durable; large diameter is the external thread (then the lens side), small diameter is the female (access to a variety of filters with the same diameter UV, CPL, Starlight, Mirror, close-up lens ... hood, etc.).
 
3, lightweight and portable, easy to install, at the same time can save money.
 
4, adapter ring big change small diameter adapter ring.