Abstract: A cap (1) is provided for fitting to the end of a hollow post. A number of hollow posts are used in viticulture to support wires on which grape vines are trained to grow. Caps (1) are fitted to the ends of the posts to inhibit snagging of netting which is placed over the posts to attempt to protect a crop of grapes from being eaten by birds. The cap (1) has a generally domed head (3) and a stem (5). The stem (5) has at least one radially outwardly extending abutment (13, 15) which, in use, engages with an inner wall of a hollow post. The abutment (13, 15) provides an interference fit of the stem (5) in the post such that to insert the stem (5) substantially all the way into the post requires force fitting and either deformation or shearing of material from the abutment (13, 15).