3498 x 1. This is generally  known as the MK2 Jaguar design of clutch slave cylinder, long body Type (100mm). Original Number C29801

NOTE : Sometimes customers find they have this cylinder fitted, operating a long 'paddle fork' (instead of the correct XK150 slave cylinder that sits on a steel, perpendicular bracket 3499), but fitting of it is only possible if  *THE BELLHOUSING IS NOT A CORRECT XK120/140/150 UNIT *.

TO FIT AN INCORRECT BELLHOUSING ALSO REQUIRES THE WRONG STARTER MOTOR TO WORK and often incorporates incorrect matching flywheel (104 tooth) and gearbox, fitted as a complete transmission assembly.