From their website:
Continuing our march through time, we’re very happy to introduce our new series dedicated to the American Civil War (1861–1865). These models are very detailed and accurate reproductions based on period photo and eyewitness drawings, however the same methods of constructions and materials were used for well over a century before and after this war, so you can use them for any conflict from the late 17th Century well into the 20th. This range will soon be completed by additional fortification modules, bombproof shelters and camp tents and accessories. Keep an eye on the Hoppidus range main page for an up-to-date snapshot of new models on the way.