From Halopedia, the Halo wiki
4 Delta was a UNSC Army unit operating in New Alexandria, Reach. During the Siege of New Alexandria on August 23, 2552, 4 Delta, alongside 4 Charlie, were tasked with destroying a Covenant communications jammer located in Club Errera in the Vyrant Telecom Tower. Pinned down by two pairs of Hunters, the Troopers had taken multiple casualties and were low on ammunition when Spartan-B312 arrived to provide assistance, dispatching the Hunters and deactivating the jammer.
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