S15 +5 Pre-Installed 20-Round Magazine for Glock 43X / 48

Our patented S15 Gen 3 magazine with the +5 extension and a 12-coil power spring pre-installed. Holds 20 rounds of 9mm in the Glock 43X and 48 and arrives ready to load. Remove the extension and swap the spring to carry it flush at 15. Requires a Shield Arms steel mag catch. Made in USA.
SKU: S15-ME-5INS
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Availability: In stock
$74.99
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Buy now, pay later Available at checkout on orders over $150
Compatibility

Fits the Glock® 43X and 48. Runs With a Steel Mag Catch.

This is a complete S15 magazine, so it fits the Glock® 43X and 48, all generations. It's steel, and the polymer mag catch the pistol ships with isn't compatible with it. Install our Standard or Premium steel catch, sold separately.

What Is the S15 +5 Pre-Installed Magazine?

It's our patented S15 Gen 3 magazine with the S15 +5 extension and a 12-coil power spring already installed, so it holds 20 rounds of 9mm and arrives ready to load. It runs in the Glock® 43X and 48 with a Shield Arms steel mag catch. Take the extension off and swap the spring, and the same magazine carries flush at 15. Made in the USA, with a lifetime warranty and Spring for Life.

  • Capacity: 20 rounds of 9mm (15 + 5)
  • Fits: Glock® 43X and 48, all generations
  • In the box: S15 Gen 3 magazine, +5 extension installed, 12-coil power spring
  • Requires: a Shield Arms steel mag catch
S15 +5 Pre-Installed

20 Rounds From a 43X or 48

The S15 holds 15 flush in the slim 43X/48 grip. This one comes with our billet +5 extension and a 12-coil power spring already fitted, for 20 rounds in a magazine that's ready to load the day it arrives. Nothing to install.

It extends below the grip, so most owners carry a flush S15 in the pistol and keep the 20 as a spare, a range mag or a home magazine.

20 Rounds, ready to load
15 Flush, with the extension off
12 Coil power spring, installed
USA Made, with Spring for Life
Features

What You're Getting

  • S15 Gen 3 Body

    The patented steel S15 with Gen 3's thicker, tougher steel and raised rear ribs.

  • Installed and Sprung

    The +5 extension comes fitted, with a 12-coil power spring installed to keep all 20 rounds feeding.

  • Easy-Access Floor Plate

    Reach the spring and follower for cleaning or service without taking the extension off the magazine.

  • Index Cuts

    Cuts on the billet 6061 extension give you a better grip when you pull the magazine from a pouch.

S15 Family

Flush at 15. This One Holds 20.

Every S15 extension comes pre-installed too: +2 for 17 and +10 for 25.

Want 20 in one piece? See the S20. Capacity laws vary by state and city. Check yours before you buy.

Required

Run It With a Steel Mag Catch

The S15 is steel and the catch your 43X/48 shipped with is polymer, and the two aren't compatible. Swap in our Standard or Premium steel catch, both made in the USA. Need a catch and magazines? The S15 Combo Pack 4 includes three S15s, two +5 extensions and a steel catch.

Specifications

Capacity 20 rounds, 9mm (15 + 5)
Compatible pistols Glock® 43X and 48, all generations
Magazine Shield Arms S15 Gen 3, steel, Nitrocarb (QPQ nitrocarburized) finish only
Extension S15 +5, pre-installed
Spring 12-coil power spring, installed
Extension material Billet 6061 aluminum, Type II anodized
Floor plate Easy access, no need to remove the extension for cleaning
Grip Index cuts for pulling from a pouch
Mag catch Shield Arms steel catch required (Standard or Premium), sold separately
Magwells Shield Arms Carry and Premium Magwells for the 43X/48, and most aftermarket flared magwells
Made in USA
Warranty Lifetime warranty plus Spring for Life

A Note on Mud Anodizing

Our Mud anodize shade changed slightly in 2025. Mud extensions bought before then may not be an exact match to the current shade.

Questions

S15 +5 Pre-Installed FAQ

Do I need anything else to run it?

Yes, a Shield Arms steel mag catch, sold separately. The polymer catch the pistol ships with isn't compatible with steel S15 magazines.

Can I carry it concealed?

It extends below the grip, so it's less discreet than a flush S15. Most owners carry a flush S15 in the pistol and keep this one as the spare.

S15 +5 or S20?

Both hold 20. The S20 is one piece with nothing to swap. The S15 +5 lets you take the extension off and carry the same magazine flush at 15.

Can I convert it back to 15 rounds?

Yes. Remove the extension, put the standard S15 base pad back on and swap the 12-coil power spring for a standard S15 spring.

Pre-installed or extension only?

Pre-installed gets you a complete 20-round magazine. Already own S15s? The S15 +5 Extension upgrades them.

Will it fit my magwell?

Yes. It works with our Carry and Premium Magwells for the 43X/48 and most aftermarket flared magwells.

Do I have to remove the extension to clean it?

No. The easy-access floor plate opens to the spring and follower with the extension still on the magazine.

What's covered?

A lifetime warranty against defects, plus free replacement springs for life through Spring for Life.

ODA Green

Used on: magazine extensions, magwells

ODA's (Operational Detachment Alpha) are the boots on the ground operational teams of a Special Forces Group. This color began as a special run for a deployed ODA. In continued support we have decided to continue the color as a standard offering and donate a portion of the proceeds to The Green Beret Foundation. Finish is anodized in green.

QPQ Nitrocarburizing Surface Treatment

Used on: magazines, barrels, slides

QPQ Nitrocarburizing is a type of surface treatment used to enhance the durability and corrosion resistance of metal parts. The process involves heating the metal in a controlled environment, where nitrogen and carbon are introduced to the surface of the metal. This forms a thin layer of a hard compound called "nitrides," which increase the surface hardness of the metal.

During the QPQ Nitrocarburizing process, the metal is immersed in a special salt bath and heated to high temperatures. The salt bath contains a mixture of chemicals that release nitrogen and carbon, which penetrate the surface of the metal. The process is carefully controlled to ensure that the nitrogen and carbon penetrate to a specific depth, creating a uniform layer of nitrides on the metal's surface.

The resulting nitride layer provides many benefits to the metal parts, including increased hardness, wear resistance, and corrosion resistance. This treatment helps to increase the lifespan and durability of metal parts, making them more reliable and long-lasting.

Any “scuffing” you see in the surface finish is completely normal, and will not affect the durability or corrosion resistance of the steel.

Electroless Nickel Plating

Used on: magazines

Silver electroless plating offers superior electrical conductivity and corrosion protection with excellent deposit uniformity and adhesion properties. This bright, reflective finish provides outstanding solderability and contact resistance while maintaining the consistent thickness and coverage that electroless plating processes are known for. Black electroless nickel plating provides these same exceptional deposit properties - including lubricity, hardness, and corrosion resistance - but with a fully conductive and uniform black surface finish that combines superior performance with an attractive dark appearance.

This item is controlled for export by the International Traffic in Arms Regulations (ITAR). Please check your state and local laws regarding magazine capacity restrictions.

Freedom Restricted States

If you live in a state that restricts magazine capacity we cannot ship to you unless you are law enforcement or otherwise exempt. If you are exempt from your state's ban please send us a copy of your documentation or official email to [email protected]. Please include your order number.

If you purchase from a ban state and you are NOT exempt, we will cancel your order and charge you a 5% cancellation fee.

Notice

GLOCK® is a federally registered trademark of GLOCK, Inc. and is one of many trademarks owned by GLOCK, Inc. and GLOCK Ges.m.b.H.  Neither Shield Arms nor this site are affiliated in any manner with, or otherwise endorsed by GLOCK, Inc. or GLOCK Ges.m.b.H.  The use of "GLOCK" on this and associated pages on our website is merely to advertise the sale of GLOCK® pistols, parts, or components. For additional genuine GLOCK, Inc. and GLOCK Ges.m.b.H products and parts, visit www.glock.com.

Products specifications
Firearms Manufacturer Glock
Firearms Model Glock 43X/48
Installation Help

Not sure how to install this product? Our step-by-step guides and video walkthroughs make it simple.

View Installation Guides →
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