1.2 What is the tension of the flat rubber band?

1.56 cattle. The model of the slingshot rubber band is represented by four digits, in which the first two digits represent the inner hole diameter of the rubber band, the last two digits represent the outer diameter of the rubber band, and 1240 represents the rubber band with a 2mm inner hole and a 4mm outer diameter. According to the tension of the slingshot rubber band and the number of rubber band models, the Zhang Liwei 1.56 N of 1.2 flat rubber band.