(57) An improved security seal includes a plastic housing (22) with a chamber open at one end and a plastic rotor (24) which is insertable in the chamber. The housing wall contains bores (42, 44) aligned across the chamber and two annular grooves (38, 40) adjacent the chamber entrance. Tabs (56, 58) are formed adjacent the chamber entrance. The rotor has a bore and two annular ridges (70, 72) near its top. The ridges (70, 72) are relieved complementarily to the tabs. The rotor may be partially inserted in the housing by snapping the lower ridge (72) into the upper groove (38) and locating the tabs in the relieved areas to align all of the bores so that a seal wire (26) may thereafter be inserted through the seal. The ridge-groove and tab-relief cooperation prevent inadvertent relative rotation of the rotor and housing and full insertion of the rotor. With a seal wire (26) inserted, the rotor (24) and housing (22) are relatively rotated to wrap the wire about the rotor (24). The rotor (24) is then fully inserted into the housing (22) so each ridge snaps into one groove. This and the engagement of teeth (34) on the bottom of the rotor and the chamber prevent removal of the rotor (24) from the housing (22), relative rotor-housing rotation, and removal of the wire from the seal. Cowls may surround the housing bores to obviate insertion of an object and levering out of the rotor from the housing.