Master Lock Gun/Rifle Trigger Lock, 1-1/8-in Wide x 14-in Shackle in the Padlocks department at Lowes.com
Lockforall Cable Gun Locks with Keys - Keyed Alike 15" Cable Gun Safe Lock for Pistols, Handguns, Rifles, and Shotguns, Home and Storage for Firearm Locking and Safety, DOJ Approved(15" 10 Pack)