Thermal paper ia always sold as rolls, the most common specifications are 80mm×Φ60mm、57mm×Φ50mm, the front number stans for width of paper rolls, the back number stands for diameter, error of width is 1, 2mm, which has no influence on using, because printer won't be printed on the both sides, the diameter of paper rolls is important for purchaser, total length of paper rolls have something to do with the performance of paper, if it is said that its diameter is 60mm, in fact, it only has 58mm, the length pf paper will reduce one meter ( depends on paper's thickness), in the market, thermal paper roll is labeled X0, its real diameter is shorter than X0. There isanother point that we need to pay attention to is the diameter of die in the middle of paper, some merchants will play a trick on it, they will choose bigger die, the length of paper will be shorter. Purchaser can measure diameter with a ruler and compares it with length on the label. we also need pay attention to diameter of die, in case that purchaser will be fooled by merchants.