 They were powered by a gravity remontoire, a small weight which was wound up by an electric motor every 30 seconds, to eliminate the effect of changes in drive force on the mechanism.Working Riefler precision pendulum clocks on display to the public are located at the Deutsches Museum in Munich, the National Watch and Clock Museum in Columbia PA, the Musée international d'horlogerie in La Chaux-de-Fonds and the Musée d'horlogerie in Le Locle (both in Switzerland), the Deutsches Uhrenmuseum in Furtwangen, and at the US Naval Observatory (by appointment only) in Washington DC.The clock at Carleton College in Northfield, MN is currently not on display, awaiting the completion of a new display space in Anderson Hall.