Look for a pump and spray bar that can maintain stable flow across the full operating speed range without pressure spikes. Critical features include accurate application rate control, smooth pressure regulation, proper nozzle selection for emulsions, and a calibrated distribution manifold that avoids dead zones. Tank agitation or recirculation should be gentle to prevent breaking. Heating may be required for some grades or cold climates. Easy cleaning of lines, filters, and nozzles matters because dried residue is a common source of clogging and streaks.