This device enables you to easily add leader to your rolls of 65mm film.  You no longer need to waste valuable film when loading a camera or back.  Just cut an 11" strip of used (preferably developed) film and insert it under the guided weight on the right side of this splicer.  Line the left edge of the film with the thin white line on the splicer, then let the weight hold the film in place.A loaded cassette fits perfectly in the compartment on the left side of the splicer.  Pull out a tiny bit of film, aligned with the white line on the splicer.  Hold down the edge of this film and use Scotch Magic Tape or Kodak Splicing Tape to tape across the two pieces of film.  It takes only seconds and gives you a perfectly aligned leader.  You can add leader at the beginning of each cassette load, but can also add it after any mid-roll cuts. This is designed to be used in either the light or the dark, and thus it can also be used to add trailer as well as leader.