Calendar building set for making custom calendar, with perforated sheets and plastic spiral spring able to be inserted by user

摘要

The building set for the calendar (3) consists of a number of individual sheets (1) which have a perforated strip (6) along one side edge (5). There is also a plastic spiral spring (2), the rise and thickness of which are suitable for the perforated strips, so that it can easily be screwed in by the user to join the sheets.