yes. when you set your boom's gooseneck through the mast slot'....have the first stop set low. Put the second (upper) stop set just below the mast slot so that you can feed the slugs' in and up. Once all of the slugs are in the mast track, just raise the second stop so that none of the slugs will be able to enter the mast slot! This will allow you to reef the main with out the fear of any slugs' being able to accidentally come off the mast thru the mast slot. practice getting the correct position of the lowest stop and "mark it on the mast. when in the correct position, you should be able set the fist stop at your mark, raise the second ABOVE the mast slot and set it. attach the boom and then lower the upper stop so that you can begin feeding the slugs'. once all the slugs are in, you just raise the second stop to block off the mast slot. g'luck