The D4 from Vishay Precision Group Inc., Malvern, PA, is a portable, USB-powered DA conditioner that lets you connect and monitor up to 4 channels of strain gauge input or input from any Wheatstone-bridge-based device. Features include support for quarter-, half-, and full-bridge strain gauge configurations; built-in precision bridge completion for 120, 350, and 1000 ohm circuits; 2 Hz sampling rate; fixed 1.5 V bridge excitation; 60–2000 ohm bridge impedance; automatic and manual zero balance and calibration; 0.1% accuracy; strain range of 31,000 microstrain; and 1 microstrain resolution. Application software is included. Applications include stress analysis for aerospace, automotive, agricultural, and structural testing.