Every Boy Scout or Girl Guide probably had the experience of building a simple solar oven: an insulated box, some aluminum foil, and plastic wrap, and voila! On warm, sunny, summer days, you can bake.

The Razer Nari is a decent wireless headset, but it’s a little oddball—because it uses a bespoke USB dongle for pairing. This is all well and good if you’re using a supported ...