Maxitrol 15"-30" Yellow Spring YEL R13110, For RV131 Regulators15"-30" Yellow Spring For Maxitrol RV131 Regulators. Made in the USA. Product Specifications BRANDMaxitrol COLORYellow REGULATOR COMPATABILITYRV131 SPRING RANGE INCHES15 - 30 LIMITED WARRANTY YEARS1 MANUFACTURER'S PART NUMBERYEL R13110