Looks like member CADplans loader. He designed them and sells the plans for them online. Somewhere in the archives on this site is him using it. He had one on at least one of his Cubs. They work well, and can be trusted. A one arm loader isn't a bad thing.
Here's a link to his site where you can buy the plans:
https://www.cadplans.com/cadloaderlt-model-507.html