Master Lock's 1KA-X2023 Uses A Standard K1-Cylinder, Which Is The Same Now Used In Industrial-Strength Magnum Padlocks (M1STS, M5STS & M15 Series Locks), Allowing You To Elevate Your Security Where Needed Without Blowing Up Your Key System. Master Lock No. 1KA X2023 Elevated Security Padlock Master Lock's Magnum Series Are High-Security Stainless Steel Industrial Strength Locks That Are Now Compatible With 1KA-X2023 Laminated Series Padlocks, For An Elevated Security Experience Without Adding New Key Numbers (And Keys) To Your Current System. "X2023" Magnum Series Padlocks: STS: M1KA, STS: M1KALF, STS: M1KALJ, STS: M5KA, STS: M5KALF, STS: M5KALJ KAX2023 Keyed Steel Series Padlocks: 1KA-X2023, 1KALF-X2023, 1KALJ-X2023, 3KA-X2023, 3KALF-X2023, 3KALH-X2023, 5KA-X2023, 5KALF-X2023, 5KALJ-X2023, W1-X2023 Matching Keys Lead Time: Please Expect 18-Working Days' For "X2023" Padlocks And Keys To Ship