Hot Rod Part. WrenchRat SparkArm protects spark wires from heat. Our WrenchRat Hot Rod part is a vital Hot Rod part for anyone with a hot rod generating a lot of heat. WrenchRat's SparkArm heat protetctor is a critical hot rod part. Our WrenchRat hot rod part protects your spark wires from heat. For a Hot Rod part for heat protection choose WrenchRat SparkArm Technology.