Radial vertical antennas. Consists of two wires λ/4 per band. Uses 1.5 mm2 copper braided contact leads insulated with PVC. Includes solder lug for easy connection to Earth.
This radial kits can be used for antennas with high installation, not mounted to the ground. The radials should be installed so as not to touch the ground, the roof or other obstacles. If the vertical antenna must be installed on the ground, must be used different types of radial (long at least as much as the height of the antenna, preferably longer and higher amounts possible, however no less than 10).
Some antenna manufacturers offer excellent explanations about the radial, for example SteppIR and Bencher (English):