Visico™ LE4421 / Ambicat™ LE4437 is a silane crosslinkable natural compound system designed for insulation of low voltage energy cables. Visico LE4421 is a low density polyethylene, copolymerised with vinyl silane. LE4437 is a crosslinking catalyst masterbatch specially designed to be used with Visico base resins. The system crosslinks quickly in sauna or in hot water. Cable insulation with a proper mixture of Visico LE4421 (95) parts) and Ambicat LE4437 (5 parts) exhibits excellent thermo- oxidative stability. The combination is suitable for both copper and aluminium conductors. LE4437 contains a copper passivator, which minimizes discoloration (blackening) of the conductor.