Cooper S style of valve stem seal with metal casing like a modern car, that is a tight fit on any normal valve guide. for long life, better sealing and with viton rubber are capable of withstanding todays corrosive oils. A higher performance item than adu4905.
Sold per each, but 8 usually fitted or sometimes 4 only on inlet guides. With some hi-lift cams these seals may be damaged by the valve spring cap when fitted with long collet groove valves. We will have LONG valves for small bore engines to solve this and other spring problems