This tool is a graphic installer?s relief. The 3M Textured Surface Applicator, TSA-4, is a two handed spin-off of the TSA-1. It has a lock for your heat gun and two handles to relieve the stress to the installer?s arms while installing on a rough wall. Also known as a " Rock-?N- Roller" this vinyl applicator allows a graphic installer to rest easy while getting the job done efficiently.