ARI fork seal set The quality of their execution is matched by the unique nature of the material used (XNBR). The fork seals offer unique features and find their use in modern forks of motorcycles and scooters: - Resistance to abrasion and high temperatures    ARI fork seals are of the same quality and dimension as the OE quality. This results in the best possible seal under all road and climatic conditions. The fork seals are used in everyday use, in racing or in classic cars.