This is a set of injection-plastic accessories for detailing AFV kits.
From the Airfix website:
Typical of many such checkpoints and bridges on the Western Front in WWII, this set is the perfect accompaniment for any 1:32 D-Day diorama. Featuring both the damaged revetments of a bridge and the barrier with guard house it forms an excellent backdrop. The machine gun tower with search light also offers excellent diorama possibilities.
Approximate measurements upon completion of this model kit:
- Bridge length: 310mm, width: 150mm
- Tower length: 110mm, width: 110mm