The Clue "Gets to work in just 6-seconds" antacid brand
The Answer ENO
The answer "ENO" fits the clue because it is an antacid brand known for providing quick relief. The phrase "gets to work in just 6-seconds" refers to how fast ENO can help settle an upset stomach. This quick action makes it a popular choice for people seeking immediate relief from acidity. The brand name is short and matches the crossword's requirement for a three-letter answer.