Acoustic Terrain

Brigade Models have released their acoustic mirror terrain packs:

Welcome to the start of our range of Land Ironclads (and by extension, Aeronef) terrain.

This first two items are ideal for both ranges - a pair of acoustic mirrors (also known as listening ears), based on the real WWI-era installation at Denge in Kent. They make perfect targets for bombing raids or ground assaults, or give you early warning of impending air-raids.

Rules for Aeronef can be found in issue 42 of Ragnarok, if you're able to get hold of a copy.
(and yes, I have a copy!)

http://www.brigademodels.co.uk/LandIronclads/Terrain.html