Used on the return fuel lines of OM352, OM366 to connect main return line, to smaller head return line. Common to break.
The 10x5x10 is more often found on the later SBU Unimogs.
Double Check your main polyamide fuel line as this T is sold in 2 sizes.
0029901370 = 10MM x 5MM x 10MM
0029901470 = 8MM x 5MM x 8MM