Borg & Beck Clutch kit

Jaguar: E-Type 4.2 Series 1 from engine no. 7E135501 and 7E53582 plus all 4.2 Series 2 (1968-70) • XJ6 3.4 and 4.2 with 4-speed manual gearbox (1968-79) • Mark II 3.4 from engine no. KJ8237, 3.8 from engine no LE2981 and all 340 • S-Type 3.4 from engine no. 7B6572, 3.8 from engine no 7B60391 • 420 and Daimler Sovereign (1966-69) • Mk10 4.2 (1964-66) • 420G (1966-70)

diaphragm type with 9.5" diameter, 10 splines and ball race bearing

With more traffic on our roads and lights controlling the flow, it is more common for drivers to keep the clutch pedal depressed whilst sitting stationary, as opposed to putting the vehicle in neutral and putting the handbrake on, which can cause rapid failure to a carbon bearing.
Carbon bearings were designed to withstand a short amount of contact with the cover release plate (e.g. changing gear) and will fail if left in
a prolonged, continuous contact.
It's recommended that if the car is regularly driven, then upgrade to a kit with a ball race bearing.
Ball race bearings are designed to be in continual contact and spin with the
clutch. They are therefore unlikely to fail if the driver has their foot continually on the clutch pedal. Today, all modern clutches use ball race bearings.