Press-fit lockable housing configured to attach to flexible materials

An apparatus comprising:

• a housing having a front, a back, and a side, the side having a slot that extends long a perimeter of the housing, the housing having a plurality of corners;
• one or more electronic devices located in the housing;
• and
• a ring having a variable-width wall along a circumference of the ring, the variable-width wall measured with respect to a radius of the ring, the variable-width wall defining multiple sets of internal surfaces, each set of internal surfaces configured to be aligned with the corners of the housing at different rotational positions of the ring relative to the housing, each set of internal surfaces defined by a respective width of the variable-width wall to define a respective gap between each corner of the housing and a respective set of internal surfaces when the corners are aligned with the respective set of internal surfaces,
• wherein when a flexible material is located between the housing and the ring, the apparatus is configured to form a press-fit lock when the ring is rotated relative to the housing to attach the apparatus to the flexible material.