Master Lock Black Covered Aluminum Padlock, Gym Locker Lock with Key for Indoor or Outdoor Use with Vinyl Weather Resistant Cover, 141D

If you are in the US, you can get them on Amazon. Edit: https://a.co/d/0bGNqkX8 https://a.co/d/08YK12yS Also, if your local hardware store doesn't carry them, Home Depot and Lowe's often do.