Spreader Where Can I Find The Spreader Bars That Are On A Ladder For A Project We Are Doing,?

Where can I find the spreader bars that are on a ladder for a project we are doing,? - spreader

make a ladder to a loft area in our little hut, must somehow come together to drop the scale on the side, but the extent is the development of the fund for the children to climb. no idea. Thoughts on the use of the spreader bar of a ladder, but can not find