Abstract: A locking mechanism of the barb type is provided for releasably locking two elements together. One of the elements has two pairs of opposed barbs or hook type resilient members. The barbs or hooks of each pair facing each other and being spaced apart. The other element has a pair of opposed, spaced ledges with downwardly facing surfaces engageable, in a locking relationship, with the barbs. An appropriate size opening is provided in the first element above the opposed pairs of barbs. The opening is a round central portion and a pair of side lobes coextensive with the opposed pairs of barbs. A separate key having a central rotational axis is provided. The key has a handle, an intermediate round portion connected to a working end portion, and generally oval in shape or cross section. The key is insertable in the opening such that the narrow part of the oval portion rests between the pairs of opposed barbs.

Abstract: A bait station for containing rat poison contains a housing; at least one opening in the housing for a rat to enter; and a bait position in the housing for locating poisoned bait. A divider is provided between the bait position and each opening to prevent direct access to the bait from the opening, for example by a child. However, there are at least two different routes from the bait position leading to openings. Research has shown that rats, unlike mice, prefer not to eat in a confined space and it is believed that the choice of escape routes offered by the bait station of the invention encourages a rat to eat more of the bait. The bait station may include a hinged lid with locking means to prevent tampering with the bait.