VW CV joint bolt. These CV bolts are common across VW CV joints on automatic transmissions after 1999 and 1.8t cars with manual transmissions. After 1992 VW moved to various inner CV joint designs depending on your vehicle, engine, and transmission combination. There is a longer version of these same bolts (#22418) for the cars equipped with the flat style serviceable inner joints up to from 2003 on. Pre-1999 a 8mm short (#22365) and 8mm long (#12355) version were used. If you are unsure of which size bolt you need it may be best for you to go and take one off your car and measure before you order. Sold in sets of 6, 1 set required per axle.
If you're removing your driveshaft, you'll need an 10mm 12 point Allen star tool for the inner bolts, and the 30mm axle nut socket for the outer bolt. New axle nuts can be ordered as part #19331.