A:For pre-heater plugs with 10mm across flats on mercedes CDI enginee(OM611,612,613etc) For pulling out pre-heater plugs after have been unsrewed but are still located girmly in their holes. Length:135mm Drive:19mm hex

B:Application:Mercedes 4-Valve-engines OM604,OM605, OM606 with glow plug threads Size:M12 X 1.25 Drive:13mm hex Glow plug:7mm

C:Important if the engie is difficult to start. Application:Meredes CDI-Engines 4.5 & 6 ylinder OM611,612,613 with Glow plug threads M10 x 1 Drive:10mm hex Glow plug:6mm 3PCS 3/8" DR.GLOW PLUG SOCKET Size:8,9,10 All length:83mm Chrome vanadium steel sockets in carefully selected set of size. Hardened and tempered with chrome finish for corrision restance. Handles rounded fixings as well. Set supplied on socket rail and backed by lifetime warranty these sockets have a universal joint for easy replacement and removal of popular sized glow plugs.