Check the listing for details. TapeTech Mud Head 90 Degree Inside Drywall Corner Applicator - 16TT90. Condition: New. Listed at 85.00 USD. TapeTech Mud Head 90 Degree Inside Corner Applicator TapeTech® Inside 90 Degree Applicator Heads apply a consistent base coat of joint compound for the cleanest and most efficient installation of paper-faced corner bead. Just attach this head to your corner box, MudRunner of compound tube (sold separately) and run it down the internal 90 corners. It will leave a beautiful, consistent bead of mud for you to stick your paper tape too. TapeTech stands behind their drywall taping tools with a 5 Year Warranty! Al's Taping Tools is the Largest Drywall Tool Store in the World! We are also a fully equipped automatic drywall tool service center with over 30 years in the industry. We service all major brands. All of our service techs are also fully trained in the operation of the tools that we sell and service. So if you are new to automatic drywall tools or have any questions, please give us a call. Al's Taping Tools & Spray Equipment815 Tower DriveMedina, MN 55340