Attension is the brand from Biolin Scientific that offers users a complete range of Tensiometers for all aspects of surface measurements.
Tensiometry is the measurement of surface tension with or of liquids and this can be done in different ways and with different benefits.
While there are application overlaps between the techniques it is simplest to group Tensiometers into four categories according to their principle of operation.

There is an excellent introduction to surface tension and its measurement on this Biolin link, complete with definitions and annotated video clips.
And as the CMC test is so useful and performed with force Tensiometers we also have a link to a backgrounder on this.

Force Tensiometers

Force Tensiometers measure static surface and interfacial tension of liquids. Their measurements allow determination of a number of material and surface properties, e.g. Dynamic Contact Angle, Surface Free Energy, Critical Micellar Concentration and wettability. These in turn can be used to assess adhesion, cleanliness, spreading, porosity, material solubility, biocompatibility and others like lubricity.

Force Tensiometers have become the method of choice for many to measure Critical Micellar Concentrations (CMC) of surfactants. It is also the only method to determine the absorption and contact angle of a packed powder or of fibre beds (Washburn method). It is hence used for the wettability of textiles and of individual fibres.

Attension Force Tensiometers are named Sigma models and they contain mass balances with variants to match budget and sophistication. All have the same basic principle of measuring the force of meniscus between a solid (Whilhelmy Plate) and a liquid or with push and pull modes with Du Nouy rings. Different correction models are also available for Rings (Huh & Mason, Harkins &Jordan, Zuidema & Waters etc).

Sigma 703D

The Sigma 703D is the simplest model, a stand alone unit with robust performance and specifications and at affordable pricing.

Measurements are displayed on the clear screen in real time and can be exported to a PC with the available software. The sample stage and operations are manual. Ideal for quick measurement of surface tension of liquids or the interfacial tension between liquids. CMC can be determined but it is not automatic. Temperature control is by external water bath

Sigma 702 & 702ET

The Attension Sigma 702 models are similar in analytical performance to the 703 Tensiometers but come with motorized sample stages and integrated water jacketed vessel holder. As with the 703 results are displayed on the large clear screen and can be exported for storage.

The 702 has a special variant the 702ET designed for oil/water interfacial tensions and for ASTM and IEC standards with dedicated calculation software.

Sigma 700/701

The Attension Sigma 700 models are the top end instruments with higher specifications and performance, full automation and a huge range of accessories.

A particular benefit is automated CMC testing with two optional dispensers, allowing a full CMC curve in one unattended measurement. A variety of sample holders and accessories like pH control can be mounted and software modules are available to your choice. The system is fully PC controlled.

Not only capable of surface tension and interfacial tensions but dynamic contact angle measurements, automated CMC, powder wettability, density and sedimentation.

The Sigma 700 has a wide mass range, auto calibrating microbalance suited to larger quantities of powders, heavy solids etc.

The Sigma 701 measures in a narrower range with the consequent improvement in sensitivity, ideal for fibre measurements.