Use of olefin-based plastic films for obtaining for obtaining roll tapes for closing containers, the films having a thickness in the range from 10 to 22 \u03bcm, flexural rigidity in the range 0. One embodiment includes a method that creates a communication channel between two optical transceivers and exchanges data between the two optical transceivers to determine if a fiber optic cable is properly functioning. Data reading means reads the image data sets and the accompanying information. The chamber comprises means for forming a fluidised bed. The lasers have a wavelength of 1550 nm.