A thermal detonator battle droid.
Like the B1 battle droids, Grenade droids were bipedal with two arms and two legs and had black sensors, and featured green markings to identify their model. They operated by throwing grenades at their targets. Thermal detonator battle droids carried mortars which fired thermal detonators for light anti-armor roles. These units were effective against mechanical and shielded targets and were not as effective against buildings and non-mechanical targets. Droid grenadiers carried their mortars while walking and deployed it while still.
Grenade droids were used during the Invasion of Naboo in the year 32 BBY. Grenadier droids were stationed throughout the city of Theed and were engaged by the Jedi Padawan Obi-Wan Kenobi. During the closing portion of the invasion, more of the droids tried to prevent Kenobi from taking out a quad turbolaser cannon.
One thermal detonator battle droid was used in the opening stages of the invasion. Ten more accompanied the OOM command battle droid OOM-9 during the attack on the city of Spinnaker.
More were built at Trade Federation Troop centers at the order of OOM-9.
All units of the Trade Federation Droid Army on Naboo were eventually shut down after the destruction of the Vuutun Palaa.
Grenade droids appear in the 2001 video game Star Wars: Obi-Wan. The thermal detonator battle droid appear in the 2001 video game Star Wars: Galactic Battlegrounds and its 2002 expansion pack. They were provided to the player (in the role of OOM-9) in two missions and more could be built in single- or multiplayer.