Occasionally, these numbers are associated with Everbilt or similar universal plumbing hardware, but American Standard is the primary manufacturer for this code.
(e.g., American Standard, Kohler?)
This piece is designed to stop water from running into the toilet bowl and to control the flush volume. 29759mp4
(The 3-inch is much larger and common on newer "flush right" toilets). Occasionally, these numbers are associated with Everbilt or