Complex sentence: Another innovation was a mobile pillbox that could be driven out onto the airfield, this was known as the Bison and consisted of a lorry with a concrete armoured cabin and a small concrete pillbox on the flat bed.
Split into simpler sentences: Another innovation was a mobile pillbox that could be driven out onto the airfield. This was known as the Bison and consisted of a lorry with a concrete armoured cabin and a small concrete pillbox on the flat bed.