It's a work sampling timer. When it goes off, you record what you were doing.[1][2] After a few days or weeks, a pattern of how much time is spent doing what appears. It's a management idea that never really caught on, because it's so annoying. Probably saleable as an app today, with a cloud-hosted back end.
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC225293/pdf/mlab...
[2] https://www.hca.wa.gov/assets/billers-and-providers/particip...