These new style security sockets are designed for the triangular profile, tamperproof fixings found on TDI Bosch fuel injection pump and others VW Audi Skoda Seat TDI repairs. 
Manufactured from Cr-Mo steel material.
Application: 
Specialized keys for adjusting: fuel dose, valves and fixing in injection pumps, among others, Bosch and Lucas in VW, AUDI, SKODA, SEAT with TDI / SDI engines. Injector pump driver  
5pc Kits, including 4pc impact triangular socket, size: 

• 3/8" drive 6.5mm valve wrench
• 3/8" drive 7.5mm, 
• 3/8" drive 13mm for fixing screws,
• 1/2" drive 26mm for central locking.
• 1pc Govening pressure socket.