The impossibly naïve Sniffles gets volunteered by his buddies to bell a troublesome cat. Sniffles does his best to get the bell on the nasty housecat. After several tries and narrow escapes, Sniffles accidentally bells the cat. Back with the other mice, he is now a hero. Sniffles tells them (while he crosses his fingers) that he demanded that "Mr. Cat" put the bell on.
The Cartoon Festivals print is a damaged a.a.p. print where the a.a.p. logo plays first, then the 1947-49 rings open, instead of the 1946-47 rings, notice the light blue borders. The 1939-40 version of "Merrily We Roll Along" plays instead of the 1941-45 version. The print then changes to another print that says "Sniffles Bells The Cat". This is a MGM/UA print and probably was hacked off by United Artists in the 1980s.
This MGM/UA print airs in Cartoon Network and Boomerang Latin America and Tooncast, but with the altered a.a.p. opening cut. In other countries (including the United States), this print is thankfully not seen on TV anymore and has been replaced by the 1995 dubbed version on current TV airings.