The Expansion Kit extends the The Ironclads: A Tactical Level Game of Naval Combat in the American Civil War 1861-1865 system to 1879, adds ships from major European powers of the same time period, and features some optional rules (e.g., land and land-sea action, designated targets, double/triple gun loads, sharpshooters). New scenarios also, many of them set in the American Civil War, but some in South America or Europe.
Originally issued by Yaquinto Games, a 2nd edition was released by Excalibre Games and this 2nd edition makes a number of corrections as well as features improved physical quality and graphics.
The box-cover image shown above is the Yaquinto version. If you look at the additional images below, the first one shown is the Excalibre version box, and all but one of the remaining images are of the Excalibre version.
Ironclads and Ironclads Expansion may integrate with the game: Shot and Shell by 3W.