Alvaro,
Once the new 3 piece belts arrive mid-January, you will have the option to purchase any complete pack design (including the Solo) with either the 1 piece belt or 3 piece belt. The 3 piece will be a $15 dollar upgrade from the standard 1 piece when purchasing pack and frame. The power pulls will be an accessory as well as not every customer prefers the option, they will be $5 for a set. The load shelf can be moved to front for a compression panel and is a standard feature on all frames and included when purchasing any bag with frame.
The primary difference between the 1 piece full wrap belt and the 3 piece belt is the removable lumbar pad on the 3 piece. This allow the user to vary the thickness and pressure from the pad to the lower lumbar. The foam is removable and can be trimmed or moved vertically to create a roll in the pad and adjust to lumbar curvature. Choosing between the two designs really comes down to personal preference and past experience. For example, I have fairly flat lower lumbar and do not do well with an aggressive lumbar pad, therefore I prefer the 1 piece. However, you can remove the extra layer of foam in 3 piece lumbar to make it the same thickness as the 1 piece. The 3 piece belt does give more options for customization. The 3 piece belt is 1.5 ounces heavier than the 1 piece.
Thanks for your questions and let me know if there is anything else I can help with.
Happy Holidays,
Kurt
