Aquastrength Upper Body Bells: Ideal for those focused on strength and core training. The Aquastrength Upper Body Bells (both blue and pink options are the same resistance) are considered All-Purpose Resistance similar to the Aqualogix Medium Resistance Bell. The Aquastrength Bells provide a bit more resistance than the Aqualogix All Purpose Bells in linear movements (like push/pull). Their unique open handle design makes them ideal for hand over hand and core focused movements. Some also like the larger diameter smooth grip of the Aquastrength Bells.