The S9-series heavy power droid was a 0.75-meter tall model from Veril Line Systems. It had a reinforced chassis, photoreceptors, a binary vocabulator, an internal heavy generator, heavy treaded wheels, and a six-meter extendable power transfer cable. In overall appearance, it somewhat resembled a bulkier version of a WED Treadwell repair droid. It was sold as an advanced replacement to the EG-6 power droid, which did not sell well. While the EG-6 could easily recharge a landspeeder, the S9 could recharge a starfighter. The model could handle rough terrain, making it popular with Rebel cells such as on Qat Chrystac, where several of the droids were modified to harass radtroopers.