To receive coupon for buy one Spektrum 4S 450mAh 30C battery (SPMX4504SIC2), get the second one free, you must purchase one or more UMX F-86 Sabre 30mm EDF BNF Basic (EFLU7050 ) between April 11 and April 18. Coupon will be sent via email on April 19th and good April 19th through April 30th. Limit one free battery. Free battery automatically applied in cart. Not applicable to taxes or shipping fees. No adjustment of previous purchases. This promotion cannot be redeemed for cash or cash equivalent. Prices, availability, and specifications are subject to change without notice.