CRB MHX 7'0" Med-Heavy Mag Taper Rod Blank - MB843 is the only true blank in the set and is the best starting point if you want to build a bass rod. It’s described as a versatile workhorse for worming, spinnerbaits, buzzbaits, and jigging.
Cortland Guide Series Euro Nymph Fly Rod fits if your “rod building” interest is really about a purpose-built nymphing rod profile: lightweight, fast-action, 4-piece, and focused on Euro nymphing.