A seal housing body, extruded AL or molded plastic or metal, has cavity portions communicating through an interface region formed by one at least one frangible projection protruding from the first body into the cavity, a first cavity portion for receiving a locking body, the second cavity portion forming a shackle receiving passageway. The locking body has a channel inclined relative to and in communication with the passageway. A spring in the channel urges a shackle locking ball up the channel partially into the interface region, the ball, having a diameter sufficient to pass through the passageway, is captured in the channel by the at least one projection. The locking body has indicia and/or flanges, at one or both opposing ends, to provide tampering evidence. The channel is offset from the locking body's central plane forming a single channel side wall to preclude trapping the ball by tampering.