Review on OTC 5060 Detroit Diesel Injector Socket: Ideal for GM 6.2L and 6.5L Diesel Engines by Steven Ferguson

Other reviews of poor finish on 3/8" square hole are correct. 8" wrenches or Craftsman extensions or other quality wrenches with squarer ends. But I was able to use an unnamed (probably Chinese) 3/8" extension that had a fairly rounded 3/8" end and fitted snugly into a vaguely square 3/8" hole on the socket. A 3/8" hole with a file will probably work, but I need to get that, and it shouldn't involve an expensive head. Otherwise this head seems to work fine without damaging the small fuel return hose. Notches, and a 7/8" drive option to install a gear wrench is a nice feature. SSDieselSupply has a nozzle removal head for less ($30) that has internal rubber routing and feels like it could be better finished, but lacks a built-in 7/8" drive.