The XS-PRO Digital Filter mounts are especially suited for SLRs with wide-angle and zoom lenses.The thin design prevents the mount from vignetting in wide shots.They also have a front thread for lens caps and hoods.This 007 filter is used to protect the filter from dust and scratching the lens without altering the image.The xs pro ring design is slim to prevent vignetting but unlike other slim filters you can keep this on at all times because it fits your regular lens cap.You can also screw on other filters and hoods on the front.