This is an Urban Terrain Card set used with the Battletech Combat Books by Nova. Each time a player makes a maneuver that changes range, that player draws a new, random, terrain card. The terrain cards are used to change the amount of damage a Mech may take, the amount of heat generated, or the maneuvers that the Mech may choose. There are 64 cards in this set and the terrains included are:Open Terrain, Parking Lot, City Park, Power Substation, Fuel Tanks, Rivers & Canals, Wood Buildings, Light Rubble, Heavy Rubble, Narrow Streets, Brick Buildings, and Concrete & Steel. - BoardGameGeek