Bt13 series galvanised 18 gauge brad nails and fuel to suit gbt1850k cordless gas brad nailer finish nails brads and t nails are normally of a rectangular cross section instead of being round their diameters are less than the coil and stick nails and are primarily used for finish and trim work in the construction and joinery industries they are the same width as the shank but the breadth of them is greater than the shank this ensures that their holding power is enhanced but of course the pull th