A package includes a base, a lid, and a locking mechanism. The locking mechanism includes an arm and a flexible member. The arm extends from the lid and has a first engaging structure. The member includes a flexible rib connected to a base floor, and a second engaging structure and a contact structure on a rib outer surface. The member flexes in response to a first force applied in a first direction to the contact structure and relaxes in response to absence of the first force. The member engages the first and second engaging structures based on the member being relaxed while the lid is closed. The member disengages the first and second engaging structures based on the member being flexed while the lid is closed. The lid may be opened based on applying a second force to the lid in a second direction while the member is flexed.