This blue steel mag from Triple K is for the AMT Backup chambered in .380 Auto and holds 5 rounds.
The Backup was a small concealed hammer blowback operated pistol of all stainless steel construction. The Backup featured a magazine safety and a manual thumb safety. Before AMT built them the pistol was marketed as the OMC and TDE Backup. Arcadia Machine & Tool bought the tooling and was the manufacturer until 1998, after the Backup was manufactured by Galena Industries. Galena Industries went out of business in 2001 and the AMT name is now marketed by the High Standard Manufacturing Company Inc., based in Houston, Texas.