Kasper Salto designed Fritz Hansen's NAP series in 2010. KS50 is the model without armrest and comes in several colors and is stackable in up to three chairs in a row. The back of the shell has a high gloss finish while the front is in matte nylon with a smooth texture that enhances the curved shape of the chair and naturally adapts to the body. The legs are made of steel and are available in two variants, chrome-plated or powder-coated in the same color as the shell.

When Salto designed the chair, he wanted the user to be able to sit comfortably in any position. The name NAP is an abbreviation of normal, active, and passive, the three main seating positions. Kasper Salto's design concept is a tasteful combination of classic Danish design and influences of international industrial design, which the KS50 chair exemplifies.