Know what you are buying! All Zefon pre-weighed cassettes are weighed to a 5 decimal accuracy (e.g. .00001g). Some competitive brands are only weighed with a 4 decimal accuracy and are unacceptable for some applications.
Using Zefon pre-weighed cassettes does not comply with OSHA directives which require both the tare weight and secondary weight to be performed on the same microbalance and environmental conditions. If complying with this directive is a concern, match-weighed cassettes are a good alternative way to save time and still comply with the directive.
Environmental conditions can have a significant effect on filter weight readings. When using Zefon pre-weighed cassettes, it is important that the post sample weighing is performed under the same environmental conditions used at the Zefon factory. Those conditions are set at a temperature of 68° F (± 0.1°F) and a relative humidity of 50% (± 1%).