I used to have to lengthen my caulking gun to get into hard-to-reach places. I've always done everything on time, but on a recent project I decided it was finally time to test my options. This particular extension seemed reasonable enough that it should have worked. They have a fairly solid base that screws onto the seal tube. That part was ok. They have a less thick extension tube that supposedly presses against the base unit. About halfway through the most difficult part of your gasket project, this expansion is displaced due to the pressure of the gasket running through it, creating a huge mess. This tube cannot be designed to remain attached. Some simple design changes would do it well. Do not buy this product unless you crave disappointment, goo and waste of money.