HMPE (High Modulus PolyEthylene) ropes (the chemical principle of Dyneema) - very strong and durable ropes. HMPE ropes are excellent, but they slightly stretch if they are in great tension for a long time. This property is called creep. Therefore they are not suitable for permanent guying, unlike Mastrant-M.
They are currently produced in diameters of 2 mm (3/32") to 12 mm (1/2").