Because it resides just left of center but still behind the seat, the 70LS is the hydration solution for many lowracers and other hard-shell bikes & trikes with limited tire clearance or certain frame designs. It's also the best choice for the Bacchetta EuroMesh seat (though if you want to use the built in bottle mounts on the back of the Euromesh in addition to a hydration system, then it's best to go with the C100). Basically, if there isn't much room directly behind the middle of the seat, you'll want to consider the 70LS/Double Century setup. The 70LS is happiest with a 2-liter bladder. It can be upgraded to the two-pack Double Century system; use both packs for bladders or one for gear.
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