The <b>Platinum 36" Compound Tube</b> is used for applying joint compound to internal corners, external corners, and flats with the use of an applicator head. (sold separately) Compound tubes fill like a giant syringe. Simply place the ball end of the tube into the bucket of joint compound and pull the handle. The 36" is an excellent choice for getting into tight areas. These tubes are very well built and ready to start making you much more productive with your next drywall finishing job.