# Question: StepLimiter is invoked as ProcName

Hello,

I am shooting particles in G4_AIR while setting by hand the step limit therein as shown below in DetectorConstruction.cc

``````    G4double maxStep = .1*mm; // arbitrary value
auto fStepLimit = new G4UserLimits(maxStep);
logicWorld->SetUserLimits(fStepLimit);
G4cout << "The Userlimits are: " <<  logicWorld->GetUserLimits() << G4endl;
``````

When I reduce this limit below the mean free path of , say, CoulombScat the StepLimiter takes over and the output of `/tracking/verbose 1` is like the picture below

When StepLimiter is referred as ProcName how is the energy loss dE (and any other physical quantitites) determined?

Thank you,
Alex