ned is correct, SAP do have a simplex spray system on their MD500E'S, was there last week with them training. personally have installed a number of tanks for simplex. they do not have a fire system for the 500 series. also agree with helmet fire the smallest machine that can effectively do tank work would be the AS-350B3, simplex has available a very good ( bugs worked out) system for that airframe. have many good jpegs of the systems, email me if you would like me to send a few
dr