Aqualogix Medium Resistance "All Purpose" Bells: Ideal for those focused on general fitness. The Aqualogix Medium Resistance "All Purpose" Bells are a popular option for those focusing on general fitness. They provide slightly more resistance than the Low Resistance "High Speed" Bells and a good for those wanting more of an emphasis on cardio and core strength, however, are also good for fast tempo sets and HIIT style training.