Magnetic tape cassette

A magnetic tape cassette, comprisig:

• a cassette casing having a first surface including a tape reading aperture and a second surface opposite said first surface;
• at least one recess on said second surface, each said at least one recess including opposing lateral walls, a bottom wall, a projection centrally located on each of said lateral walls and a slot extending in said bottom walls;
• and
• an elastic fitting piece for each said at least one recess, each said fitting piece forming a channel shape including two legs and a connecting portion and being symmetric about a plane passing centrally through said legs and connecting portion, each of said legs including a lug forming an enclosing mating portion, each said lug being centrally located on one of said legs and on said plane of symmetry, said connecting portion including an extending portion which extends beyond said legs;
• wherein said fitting piece is adapted to fit into said recess in either of two positions, a first position in which each said enclosing mating portion of each said lug is matingly engaged with one of said projections and said connecting portion covers all of said recess except for a portion corresponding to said slot, and a second position in which each said enclosing mating portion of each said lug is matingly engaged with one of said projections and said connecting portion is perpendicular to said bottom wall to uncover said recess, with said extending portion engagingly inserted in said slot to prevent lateral movement of said fitting piece,
• whereby said fitting piece maybe moved from one of said two positions to the other of said two positions with said plane of symmetry in either of two opposite angular orientations.