Leskinen thinks that his most important industrial design work is the unique product design program of the Exel pole project, where he was developing the product and the mould of the product simultaneously. This way the customer received both the finished product and the plastic-steel production mould from him, from which they copied the final plastic tool for the factory. His models eliminated the design errors in the factory tools and saved significant amounts of money. The picture shows the mould of the butterfly wing basket.