Push your Kleinn 230 or 630 train horns to the MAX with the "BlastMaster" air flow kit. The "BlastMaster" includes two extra solenoids, oversized 1/2" air line, and all the other fittings and tubing required to put a separate solenoid on each train horn trumpet. The individual air horns no longer have to share the air from one solenoid.... boosting the train horn sound output to a mind-blowing level. Kit is designed for Model 230 and 630 horns with the Model 307 solenoid valve.