“How steep is this climb?” Now you know! Gauge the slope of your bicycle’s ascent and descent in both Percent Slope and Angular Degrees. Easy-to-see indicator ball, not a bubble! Mounts with rugged aluminum bracket to handlebar. No batteries needed; no unreliable GPS readings. Fits virtually all handlebars 24mm to 36mm diameter. Easy-to-see Saturn yellow tube assembly. Special damping fluid controls ball movement. CAUTION: There are times when it is unsafe, while riding, to take grade readings. For maximum safety, stop bike in a safe place before you view grade indication.