Hand-arm vibration syndrome (HAVS) — vibration white finger — is an occupational disease caused by breakers, angle grinders, hammers and chainsaws. EN ISO 10819 defines how a glove's ability to reduce that vibration is measured.
The criteria
A glove qualifies as anti-vibration if its transmissibility does not exceed 1.0 in the mid-frequency band (TRM) and 0.6 in the high-frequency band (TRH). In other words: at mid frequencies the glove must at least not amplify the vibration, and at high frequencies it must cut it by at least 40%.
Realistic expectations
This is the standard's most important lesson: anti-vibration gloves are close to useless at low frequencies — and low frequencies do most of the damage. A glove is a supplementary measure and can never replace control at source: a better tool, a damped handle, job rotation and limits on exposure time.
Bear in mind too that a thick anti-vibration glove often makes the operator grip the tool harder, which increases transmission. Grip force is itself a significant factor in HAVS.