What is an Army Builder set you ask? Well, we are happy to explain!
An Army Builder is a new type of plastic set we are experimenting with. It's designed to let you build the bulk of your forces with a minimal amount of assembly and for a great value. Instead of 30-40 models in the box, you get a whopping 60 for the same price ($34.95 / £25) but with less parts to stick together. In this case, there is also no command included and you will have to source command from another manufacturer in either metal or plastic. This gives you the flexibility to set the ratio of command to troops in your unit depending on which set of rules you play. If you want 12-man, 24-man, 36-man, or 124-man units have at it!
This is partial text from the full article (usually with photos) at https://modelgeek.com/news/napoleonic-prussian-reserve-army-builder-set