In Finkelstein reaction, which reactants are used

$\underset{\text{Ethyl Bromide}}{{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{Br}}+\mathrm{NaI}\underset{\text{Heat}}{\overset{\text{Acetone}}{\to }}\underset{\text{Ethyl Iodide}}{{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{I}}+\mathrm{NaBr}$

This reaction is called "Finkelstein Reaction"