Mastic gun. These guns are used to apply a variety of mastic adhesive, silicon and sealents.The power pro, takes trade and do it yourself size tubes. The carpet fitter will find the trigger action on this gun is very smooth and does not jamb so easily. This is the very best gun we have come across well worth the investment. There are cheaper mastic guns but this gun will last and prove its worth. This product has a space in anyones tool box.