The Certina 28-161 watch movement features an open face calibre design with an early common spring that was later enhanced with separate springs for the operating lever and balance stop. Throughout its production period, various additional detail modifications were made. This movement includes a timer function with options for intervals of 60 seconds (accurate to 0.2 seconds) and 30 minutes, facilitated by a pillar wheel mechanism. Additionally, there is an option for intervals of 30 seconds (accurate to 0.1 seconds) and 15 minutes, as well as an option for intervals of 3 seconds (accurate to 0.01 seconds) and 90 minutes. The movement is stem wound and incorporates a sweep second hand and sub minute display.