Concealment: Jacket, Slick
These tiny grenades, each the size of a marble, are made of an experimental substance which detonate into a miniature explosion when it impacts on a surface with sufficient force. The common method of use is either to scatter them from a higher position onto an enemy below, or to either drop them behind or set them up on a floor where a pursuing enemy will step on them.
A packet of marble grenades is about a hundred, will cover five one-meter squares and can be spread with an action. They need darkness or some concealment, such as grass, to work well.
Marble Grenades are a Traps, and uses the normal rules for discovering traps. An Intrusion or Perception roll against a difficulty of your FixIt or Intrusion will discover it. Specifically looking for traps gives a +3 bonus. Marble Grenades whose presence is known are less dangerous the difficulty is only 5 in such cases. Running through a field of marble grenades is dangerous even if their presence is known it disallows the use of Intrusion, forcing the runner to rely on Perception alone.
Stepping on any of the marbles will cause a chain reaction, making them all explode. Anyone anywhere in the area when they explode take damage 15, but those just a meter outside it are safe.