American Standard 4040 Color:Regency Blue We are not positive but

We are not positive but believe the hole is used for some kind of locking mechanism

Lid P/N: 735082

Lid P/N: 4086 or 735010

Tank Size: 21" x 7

Tank P/N: 4430 & 4432 & 4433 & 4440 & 4442 & 4443 & 4800 & 4802 & Proflo 3112 & Proflo 3212 & Proflo 3312

American Standard 4040 Color:Regency Blue We are not positive butManufacturer: AMERICAN STANDARD Lid P N: 4040 Lid Size: 22" x 8. 125" Tank P N: 4040, 4041, F4041 Tank Size: 21" x 7. 25" Toilet Model: Note: Very important! This part number is often confused with 4049. The lids physically look similar, but this one is extremely rare. The 0 and 9 are stamped poorly most of the time making some people believe theirs is stamped 4040, when it is actually 4049. The difference is easily to tell by measuring. If your tank