Anti-vibration system
The set of rubber buffers or steel springs that separate the engine unit from the handles, reducing the vibration transmitted to the operator's hands. Its effectiveness is what the declared front and rear handle vibration figures measure.
Anti-vibration mounts exist to prevent hand-arm vibration syndrome, a permanent condition, so they are a health control and not a comfort feature. They are consumable: rubber hardens and cracks with heat, fuel and ultraviolet light, and worn mounts also let the handle move sloppily relative to the engine, which you can feel as vague control. Inspect them for splits and excessive play at every major service, and replace them as a set. Keeping the chain sharp does as much for vibration exposure as any mount, because a sharp chain pulls itself into the wood instead of chattering.