TR-WVTR-9003 is based on the electrolytic sensor method and available for the water vapor permeability test of flexible films, sheeting and packages. 
Films: 
Plastic films, aluminum foil, aluminized films, plastic composite films, paper-plastic composite films, coextruded films, aluminum foil composite films and many others.
Packages: 
Plastic, rubber, paper, paper-plastic composite, glass and metal packages, e.g. red wine bottles, blister, various plastic bottles, Coke bottles, peanut oil packages, , vacuum bags, metal three-piece cans, plastic packages for cosmetic, soft tubes for toothpaste, jelly and yogurt cups.

1.Electrolytic sensor method
2.Patent technology
3.Film and package test
4.one specimen test
5.One-button test, test automatically in whole process
6.Multiple test modes optional
7.Data curves display
8.Computer control
9.Digital flow adjustment
10.Chamber temperature sensor embedded in 
11.Environment temperature and humidity sensor inside 
12.Chambers water bath technology 
13.Unit based on embedded system,24bit Δ-Σ AD 
14.Pressure, ppm water sensor and  temperature overload protection 
15.Traceable reference film calibration
16.Supports DSM system (DSM, lab data management system)
Principles
Film:
The specimen is clamped between the upper and lower chamber, the upper chamber is purged by high humidity nitrogen stream, and the other side of specimen, lower chamber is purged by a stream of dry nitrogen, due to the effect of water concentration gradient at two sides of the specimen, water molecules will permeate through the specimen into the dry nitrogen side, penetrated water molecules will be carried to the electrolytic sensor which generates the proportional signal, so water vapor transmission rate will be obtained by calculating the sensor signal.
Package:
The package is mounted on the lower chamber, the outside of the package is specified relative humidity, the inside of the package is purged by a dry nitrogen stream, water vapor will permeate through the wall into the inside of the package, penetrated water molecules will be carried to the electrolytic sensor which generates the proportional signal, so water vapor transmission rate will be obtained by calculating the sensor signal.