Completely redesigned inside and out, the $250 Powerbeats Pro 2 feature Apple's H2 chip, a new built-in heart-rate sensor and active noise canceling for the first time. Are they better than Apple's ...

Diamonds and other gemstones are weighed in metric carats: one carat is equal to 0.2 grams, about the same weight as a paperclip. (Don’t confuse carat with karat, as in “18K gold,” which refers to ...