Fun fact: The 9V, aka “Power Pack 3,” battery was originally part of a whole series of Eveready “Power Pack” batteries, most of which featured the signature “snap” terminal connectors. Today the 9V is the only battery in common use that still has these positive-locking connectors. And frankly, they intrigue me. What other clever, tiny devices could we design for batteries to clip onto, instead of into?
Besides the clever clip-on feature, I dig the Blocklite as an exercise in minimalism: it’s not much more than a 9V battery snap, six bright white LEDs, and a three-position center-off switch. Switch left to illuminate all six LEDs, right for just the middle two. The bundled Eveready PP3 was still giving usable light after 96 hours of continuous operation on the bright setting. It measures, weighs, and costs just a hair under 1 inch, 10 grams, and 10 bucks, respectively, and totally justifies every unit.