Babcock Noell GmbH (BNG) and the Institute for Beam Physics and Technology (IBPT) of the Karlsruhe Institute of Technology (KIT) are collaborating in an R&D program focused on the development of superconducting undulators (SCUs). After successfully completing SCU15, a full scale 15 mm period length device installed in ANKA in 2015, the team developed SCU20 a second device with 20 mm period length. The goal of SCU20 is to develop a commercial product. During the conceptual phase over 90% of the components have been redesigned with focus on reproducibly and reliability of the manufacturing process. Moreover the reduction in weight of the cold mass and the optimization of the cooling system, led to faster cooldown and reduced thermal gradients. This contribution describes the performance of SCU20 and the most significant design improvements in comparison to the previous generation device.