The FAB Defense Magazine Extension is a floor-plate replacement built specifically for the Glock 42 in .380 ACP, brand part number FX4210B. It adds four rounds to the factory magazine for a total capacity of 10 rounds, while an innovative spring plate design lets the extension work with the original factory magazine spring instead of requiring a proprietary replacement. The ergonomic body enables a full, secure grip on the magazine and the handgun during manipulation, with contoured finger indents that give a firm hold when seating or stripping the magazine. Molded from fiberglass-reinforced polymer, it is a lightweight, purpose-built upgrade for the Glock 42 only.

Key Specifications

• Chambered for .380 ACP.
• Fits the Glock 42 only.
• Adds 4 rounds of capacity to the factory magazine.
• Brings total capacity to 10 rounds.
• Enables a full grip on the handgun during use.
• Contoured finger indents give a firm grip during magazine manipulation.
• Innovative spring plate allows use of the original magazine spring.
• Built from fiberglass-reinforced polymer.
• Weighs 37 grams.

Frequently Asked Questions

What pistol does this fit? The Glock 42 in .380 ACP only.

Does this require a new magazine spring? No, the spring plate design lets you keep using the original factory spring.

How much capacity does it add? Four rounds, bringing total capacity to 10 rounds.

Buy the FAB Defense Magazine Extension

Add capacity to your Glock 42 with this extension from FAB Defense, part of our handgun magazines lineup. Order it from our Lubbock, Texas gun shop for fast, direct shipping right to your door.