is able to penetrate the frontal hull armour of the Challenger II and also managed to damage a M1 Abrams. As well, even tanks with advanced armour plating can have their tracks or gear cogs damaged by RPGs, which may render them immobile or hinder their mobility. Despite all of the advances in armour plating, a tank with its hatches open remains vulnerable to Molotov cocktail (gasoline bombs) and grenades. Even a "buttoned up" tank may have components which are vulnerable to Molotov cocktails, such as optics, extra gas cans and extra ammunition stored on the outside of the tank. Avoiding detection A tank avoids detection using the doctrine of countermeasures known as CCD: camouflage (looks the same as the surroundings), concealment (cannot be seen) and deception (looks like something else). Camouflage Camouflage can include disruptive painted shapes on the tank to break up the distinctive appearance and silhouette of a tank. Netting or actual branches from the surrounding landscape are also used. Prior to development of infrared technology, tanks were often given a coating of camouflage paint that, depending on environmental region or season, would allow it to blend in with the rest of its environment. A tank operating in wooded areas would typically get a green and brown paintjob; a tank in a winter environment would get white paint (often mixed with some darker colors); tanks in the desert often get khaki paintjobs. The Russian Nakidka camouflage kit was designed to reduce the optical, thermal, infrared, and radar signatures of a tank, so that acquisition of the tank would be difficult. According to Nii Stali, the designers of Nakidka, Nakidka would reduce the probabilities of detection via "visual and near-IR bands by 30%, the thermal band by 2–3-fold, radar band by 6-fold, and radar-thermal band to near-background levels. Concealment Concealment can include hiding the tank among trees or digging in the tank by having a combat bulldozer dig out part of a hill, so that much of the tank will be hidden. A tank commander can conceal the tank by using "hull down" approaches to going over upward-sloping hills, so that she or he can look out the commander's cupola without the distinctive-looking main cannon cresting over the hill. Adopting a turret-down or hull-down position reduces the visible silhouette of a tank as well as providing the added protection of a position in defilade. Working against efforts to