The title references M.4/12, a Thai Mathayom 4 classroom, suggesting this recording was uploaded by students sharing their own school bell. Electric school bells like this are common across Thailand for marking lesson changes throughout the day. Clips of familiar school sounds spread on soundboards and in group chats because former students recognise them instantly. This version is mainly shared for nostalgia, pranks in class chats, and as a ready made transition sound for school videos made by Thai students and creators online today.