Abstract: A disposable one-piece security sealing device primarily intended to surround the neck of a bag or like package comprises a strap (1) having an enclosure (3) at one end defining a passage (4) through which the other end of the strap is irremovably insertable to an adjustable extent as a result of interaction between a plurality of teeth spaced in a row along the strap with a resiliently deformable member (4b) which is integral with the housing and situated at or adjacent a bend (4a) in the passage; characteristically an identity or pull-off tab (6) is formed as an extension of the strap around and beyond the enclosure for tearing when required along a line of weakness which extends round the enclosure (3) and terminates in a side edge of the strap. By tearing along that line the end of the strap having the tab (6) is separated from the enclosure (3). There may be two rows of teeth on the strap and the enclosure would then have a passage formed with two channels to accommodate the respective rows of teeth.