For 10" speakers, the most common combo amp and speaker cabinet configurations are 2x10" and 4x10". For speaker cabinets, 2x10" and 4x10" are the most widely used, although 8x10" cabinets are used in stadium concerts, especially in louder rock genres. Other configurations with 10" speakers do exist, but they are less common. For example, there are a small number of 1x10" and 3x10" combo amps and speaker cabinets, and a small number of 6x10" cabinets. Bass speakers are usually made with stiff paper cones. Hartke combo amps and speaker cabinets are unique in that the cone is made from paper, except for the middle, which is made of aluminium. Gallien-Krueger's MB210-II combo amp uses ceramic speakers.