(Business 2.0) – A tad too large to qualify as nanotechnology, but still as tiny as a speck of dust, MEMS are making a big splash. Once considered a laboratory novelty, MEMS are functional micromachines that use mechanical pumps, valves, cantilevers, gears, or switches to perform physical tasks. Now they're beginning to appear in commercial applications such as consumer electronics and automotive systems. The breakthrough? Inexpensive manufacturing techniques that stamp out micron-size mechanical assemblies in much the same way that circuits are etched on silicon to create processor chips. MEMS nozzles are already used in ink-jet printers, and MEMS velocity sensors tell most new cars when it's time to trigger airbags. Untapped opportunities lie in the fields of medicine and telecommunications, where MEMS pumps could provide precision-controlled drug delivery systems, while MEMS optical switches could reduce the cost and complexity of fiber-optic networks. --DAVID PESCOVITZ

MARKET SIZE, 2003: $3.9 billion MARKET SIZE, 2007: $8.3 billion (projected) COMPANIES TO WATCH: Agilent Technologies, Analog Devices, BEI Technologies, Microfabrica, Motorola