Every Tribute gets to carry one non-weapon item into the arena as a “token” from their district. Katniss carries her Mockingjay pin in both the first and second Games. Peeta, in the 75th Games, wears a medallion. Effie made the medallion upon Peeta's request. It contained pictures of the three people (other than Peeta) who Katniss' cares about most in the world; Prim, her mother, and Gale.
“Peeta hoped the reminder of what she has to live for would motivate her to try to survive the Games, rather than sacrificing her life to save him, as she intended.”