2X BatteryJack FNB-29A Battery for Vertex Standard VX500 & More-18 Month Warranty 7.2V Ni-MH 1850mAh Fits Vertex Standard VX500, VX510, VX520, VX530, & VX537 Radios. Uses the highest quality A GRADE cells FREE SHIPPING US 48 ONLY 18 MONTH WARRANTY