Three F-35Bs were officially delivered to the US Marine Corps during ceremonies at MCAS Yuma, Arizona, on 20 November 2012. The aircraft are assigned to Marine Fighter Attack Squadron 121 (VMFA-121) residing with the host Marine Aircraft Group 13 (MAG-13). The delivery of the first three operational-coded F-35s marks the beginning of STOVL tactical operational training at Yuma. The aircraft increase the number of STOVL aircraft delivered to the Marine Corps to sixteen and bring the total number of F-35s delivered in 2012 to twenty. Currently, thirteen Marine Corps STOVLs are assigned to the 2nd Marine Aircraft Wing's Marine Fighter Attack Training Squadron 501 (VMFAT-501) at Eglin AFB, Florida where they are used to support pilot and maintainer training.