Strottner-Drechsler Object 4 / SNR G210.5+1.3 is a spectrum confirmed previously unknown supernova remnant in the constellation Monoceros discovered by our team of Marcel Drechsler and Xavier Strottner in August 2019.With a diameter of 25 arcminutes, SNR G210.5+1.3 is one of the smaller supernova remnants, which suggests a relatively large distance. Since no central star in the form of a neutron star, or a pulsar could be found so far, it was not possible to determine the exact distance of SNR G210.5+1.3.Examination of the spectra showed strong [SII] emission compared to H-alpha with some evidence of [O I] emission. Combined with the shock-like appearing filaments at some locations, it is fairly certain that this is an SNR. G210 could also be quite old, since there is only faint [O III] emission, and given its relatively small size of 25 arcminutes, is also likely quite distant. In addition, the SNR could be behind a considerable amount of ISM dust, since no H-beta emission is visible in the spectra.What is special and surprising about this supernova remnant is the amazingly precise separation between the ionized hydrogen H-alpha (red) and the ionized oxygen [OIII] (blue), which seems to break out of the main structure like a bubble.