The Bedol water clock adds a touch of green to your timekeeping. You never have to wind it, and it requires no batteries or any electricity. It runs on a touch of salt and few ounces water. The electrodes inside harvest energy from the salt water, powering the clock. The feature set is pretty bare — the clock has no alarm or radio — but at $16 it’s fun and cheap. The Bedol Water Clock comes in four colors.