The tester is constituted of glass tubing containing a reagent.
Tube weight is 5 g.

The reagent has for function to indicate the alcohol concentration in the air exhaled.
The reagent alters from yellow to green in colour proportionate to the density of alcohol.

A volume measurement of exhaled breath is calculated by a red thermochrome indicator.

The indicator becomes red after 2 minutes following the test.
This red colour signals the readiness to interpret the test result.

The reagent is maintained firmly between two stainless steel gates.
The tube of glass is sealed at each extremity by an aluminium core.

Striker tips are placed at each end of the tube to prevent damage due to shock.

An adhesive label is surrounding the glass tube for an increased resistance to shock.