3 Piece Hourglass Sand Timer Set with 5, 15, 30 Minute Sand Timer. This Bright Coloured Set is The Perfect Visual Timer aid for Kids. (3 Piece Set:5,15,30mins) : Amazon.com.au: Kitchen & Dining
3 Minutes 30 seconds countdown Timer - Beep at the end | Simple Timer (three min thirty sec) - YouTube
30 Minute Timer Circuit Using 555 IC and 7555 IC
3 Minute and 30 seconds Timer with Music - YouTube
3/5/10/15/30 Minute Timer Hourglass Student Time Hourglass Gift Decoration - Temu
3 Minute Timer with Relaxing Music and Alarm - YouTube
Amazon.com: Sand Timers, Mosskic Hourglass Timer 1/3/5/10/15/30 Minutes Sandglass Timer for Kids Games Classroom Kitchen Home Office Decoration(Pack of 6) (Multicolor) : Home & Kitchen