On the southern slopes of Rinjani, the Kelelawar waterfall is accessible by a spectacular 1½km walk (one way) through rice fields from Tetebatu. Walk 1km further and you'll reach Koko Duren, tucked into a steep ravine. The path is not easy to follow so you'll need to hire a guide, who can take you to both waterfalls for 300,000Rp.