From The TimeSplitters Wiki

Appearing in all the timesplitters games, the remote mine has become a well known item. When thrown on a surface or certain items, it will stick to them and wait. The player must then activate them, usually just by a button press, but in TSFP the player had to take out a switch to activate them. A remote Mine can also be activated if shot by a bullt or hit by an explosion. They have appeared differently in all the Timesplitters games.