Sandia Aerospace has developed a low-cost standby display, the SAI 340-Quatro, which retails for $3,595. The Quatro provides airspeed, attitude, altitude and slip indications in a lightweight instrument that fits into a standard three-inch instrument hole. The Quatro weighs half a pound and is just 1.4 inches thick. The unit’s lithium-polymer battery provides power for up to two hours. Certification is pending.