Element blokujący synchronizatora (kamień widełek skrzyni biegów, wysoka-niska) ZF AS TRONIC 12 AS 2001 BO, 12 AS 2301, 12 AS 2301 IT, 12 AS 2301 IT ASF, 12 AS 2331 TD, 12 AS 2530 SO, 12 AS 2530 SO W,