I will present results on the latest planet to be studied by the Low Resolution Ground-Based Exoplanet Atmosphere Survey using Transmission Spectroscopy (LRG-BEASTS, “large beasts”), the hot Saturn-mass planet WASP-39b. WASP-39b has one of the most cloud- and haze-free atmospheres of hot, giant planets, which show a remarkable diversity across the population, from clear to cloudy atmospheres. LRG-BEASTS will sample this diversity with observations of 17 exoplanets covering a broad range of temperatures and masses. LRG-BEASTS is pioneering the use of 4-metre class telescopes for low resolution transmission spectroscopy and has demonstrated that such telescopes can provide precision comparable to VLT and HST.