Even snail mail is getting a tech upgrade. This month TrackingtheWorld, a California-based GPS developer, expects to begin mass-producing Letter Loggers—small GPS-equipped envelope inserts that could help the U.S. Postal Service spot bottlenecks in the system. The insert is durable enough to shoot through sorting machines without crushing the circuits. A high-gain antenna pulls info from a satellite every few minutes and records the letter’s location to a memory card (to prevent interference with other devices, it won’t transmit data in real time).