Dawson et al. have presented the full data release for the Southern Parkes Large-Area Survey in Hydroxyl (SPLASH) — the most sensitive large-scale survey of hydroxyl (OH) to-date. The survey of the Southern Galactic Plane was undertaken in all four ground-state transitions of the OH radical at 1612, 1665, 1667 and 1720 MHz with the Parkes 64m radio-telescope, “Murriyang”. The team identified numerous new examples of satellite line ‘flips’ – a characteristic profile shape in which one line flips from emission to absorption, and the other the reverse -– across closely-blended double features. They confirm a preferred velocity orientation for these profiles, with the a 1720- emission/1612-absorption component seen at more negative velocities in the majority of cases. This is consistent with recent models explaining the flip as a signature of HII (ionized hydrogen) region expansion. The figures above show illustrative examples of satellite line ‘flips’, The paper has been published in Monthly Notices of the Royal Astronomical Society .