The first spores I ever grew, over 25 years ago, were B+…I grew them for 20 years before they produced the dark pigmented El Choco mutation. A few years later, El Choco then produced a semi-revert….not quite a return to the original B+, but a lighter cap color that still retained Choco’s slower growth and density. Its name reflects its “B” origins, but upgrading the “+” to an exponent to reflect on its improvements over the original…this is a good intermediate speed grower that bridges the gap between easy outdoor type cubes and the more challenging PE types.