Shimano's newest and best dyno-hub. It's billed by Shimano as "Ultegra" quality, although it's not in the Ultegra group. It's the lightest dyno-hub Shimano makes, by about 100g (3+oz.), and in the totem pole of dyno-hubs it ranks toward the middle in price, near the bottom in weight.
Several RIV-staffers have and love the much more expensive Schmidts, which we sell on complete wheels, and which you can also get (even as separate hubs) from Peter White. Peter probably knows more about generator lights than anybody, and probably has some thoughts on the Shimano--how it compares with the Schmidts he sells.
But in any case, Shimano certainly has the engineering know-how to make a fine bike part, and over the past several years has offered ever-improving dyno hubs, with this one being its current best.
All dyno-hubs are heavy. This one, without q/r skewer, weighs 17.1oz, about 3.2oz less than the Schmidt. But to pick a dyno-hub based on a small weight difference like that...misses d point!
477 g, 6V 3 watt, 32 or 36 hole