[en] Two 90⁰ uniform field magnets are to be installed in the Nuclear Structure Facility (NSF). Their purpose and design are summarized. The effects of various field errors on the performance of a 90⁰ double focusing magnet were investigated using a beam optics programme. The results were used to draw up the specification for the magnets. Subsequent checks were made on the angles β of the effective field boundaries with and without the field clamps in place and of the uniformity of the field along the beam orbit in the orbit plane. Checks were also made on radial uniformity in the orbit plane. In order to ensure reliability of calibration of the magnetic field in terms of the field at the NMR probe, reproducibility of field distributions for various excitation cycles was studied. Finally the performance of the magnets was checked directly using high quality α-sources located at the object point, detecting the image at the image point using a position sensitive surface barrier detector. The results of studies on the inflector magnet have been published. (author)