Profile: RWC Testing & Lab Supplies is a distributor of tachometers, stroboscopes, pH meters, conductivity meters, microscopes, refractometers,static meter, tension meters, wall mount/portable gas detectors, oxygen meters and turbidity meters. We also offer laboratory glassware, such as flasks, beakers, cylinders, hydrometers. Our DT-107A contact tachometer measures rotational and surface speed, as well as length. Built-in selector switch permits the user to display readings in a wide variety or engineering units. The DT-107A-12 includes a 12 inches circumference measuring wheel, which is offered for safer and easier surface speed measurement by keeping the users hand farther from the moving surface, and slowing down the rotational speed. All models are supplied as a complete kit including 6 inches circumference surface speed wheel, two cone tip adapters, funnel tip adapter, shaft extension, two AA batteries, and an operating instruction manual. The wall-mount toxic gas or combustible gases detector with audio/visual alarms and relay contacts, provides continuous open/enclosed space monitoring. The basic unit has a detecting sensor and controller joined together. If necessary, remote sensor with explosion-proof junction box housing, and 50 feet cable wire connection are also available. All the models can provide either 4-20 mA or 0-1 VDC output for data acquisition purpose, and PLC interfacing.