The Fusion 2.0 is a salute to the original Karhu ‘fusion' model from 1996 when it was the top running shoe in the collection. To bring back the ‘Fusion' from the archives, Karhu reworked the model with its original designer and launched it as the fusion 2.0. pigskin suede soft mesh rope laces New to the fusion 2.0? Unisex sizing in US men's. Founded in Finland in 1916, Karhu initially gained international recognition in the 1920s through Finland’s phenomenal track team who became known internationally as the Flying Finns. Since then Karhu has been at the forefront of performance and innovation in athletic footwear including developing the first air cushioned sole in the 1970s and Fulcrum technology in the 1980s.