In both lines their products are mostly known for its woofers and subwoofers capable of delivering high sound level output with comparatively low frequency ranges using comparatively low power input, as well as the red ring commonly found on the surround of many of their speaker drivers over the decades.
The passage describes a company known for its powerful woofers and subwoofers that are efficient in producing high sound levels with low power consumption. The red rings around their speaker driver surrounds are also mentioned, highlighting a consistent design element across their products.