Screen Tight BCAP18 Screen-Tight Cap Component (Pack of 20) Screen (not included) is rolled into place and cap snaps onto base (not included) and evenly tightens the screen without the use of staples, lattices, nails, or loose screens. 1-1/2" caps are used to accommodate 2" x 2" framing and 3-1/2" caps are used to accommodate 4" x 4" framing. When rescreening, the cap temporarily pops off. May use fiberglass or aluminum screening. Can be cut with utility shears or tin snips.