One cricket ball is the same as the next one, right?
Yes, they can come in different colours - red, white, pink - but two of the same shade will surely be the same?
Not quite. And it is for that reason that the England and Wales Cricket Board has asked manufacturer Dukes to revert to an old model for this summer's Ashes series.
The idea is that the older ball - the one used in 2017 and 2018 - will continue to produce entertaining Tests.
Confused? Let's try to explain.
What's the difference?
The subtle difference between the 2017-18 ball and its 2019 counterpart is the newer version has a less prominent seam.
The seam is the stitching that holds the ball together and, in theory, a more prominent seam allows bowlers to extract more movement.
The 2019 ball was made in such a way at the direction of the ECB with the balance between bat and ball in domestic cricket in mind.
When County Championship matches are played at the extreme ends of the summer, it can be harder for batsmen, so using a ball with a less prominent seam would lead to a more even contest.
The idea, in conjunction with an effort to improve pitches and the reintroduction of heavy rollers, has worked. At a time when England have been struggling to find top-order batsmen, a great number of runs have been scored in the early weeks of the County Championship.
However, on Test pitches that tend to be flatter, the newer ball may have led to contests dominated by batsmen.
Therefore, the ECB have opted for the older-style ball, hoping to replicate past summers when England have been involved in entertaining series against South Africa and India.
"We've seen some really good Test cricket in this country over a number of years," said ECB managing director Ashley Giles.
"The concern was the new ball would make conditions too batsman-friendly on good Test wickets."
Will this help England?
England's primary weapon in home conditions is the movement generated by the likes of pace bowlers James Anderson and Stuart Broad.
For that reason, it can be argued using a ball that is likely to move more will give the hosts an advantage as they bid to regain the Ashes.
But Giles asserted there was no ulterior motive to the decision, one taken after discussions with Cricket Australia.
"What we didn't want is to appear that we are doing this underhandedly," said Giles.
"It's not like we're coming up against an attack that isn't very good. The Aussies are quite handy themselves.
"Clearly Jimmy Anderson is one of our best weapons and we want to bring him into the game, but Australia also have a formidable attack."
The first of five Ashes Tests begins at Edgbaston on 1 August. Prior to that, England play a one-off, four-day Test against Ireland at Lord's on 24 July.