The Project X Injector Experiment (PXIE) at Fermilab contains one cryomodule of Single Spoke Resonators operating at 325 MHz with a geometrical beta of 0.2. Two prototypes have been tested successfully at high gradients in the Fermilab Vertica l Test Stand (VTS). We have welded a Stainless Steel helium vessel on the first prototype and tested it in the spoke-dedicated Test Cryostat. With excellent results in hand, an order for ten bare resonators was placed with US industry. A new design for th e helium vessel was developed for these resonators with the main goal of reducing the sensitivity of the resonator to variations of the helium pressure to meet the requirements of PXIE. A new tuner was developed despite the good results of the first proto type. The new design was inevitable due to the different behavior of the resonator in the new helium vessel. Other aspects were improved such as the maintainability of the tuner motor and piezoelectric actuators allowing their replacement from access port s on the cryomodule's vacuum vessel.