--- title: "Sig Sauer MPX K Black 9mm Folding Brace" description: "Black 9mm MPX K with a 4.5\" barrel, PCB folding brace, gas-piston operation, M-Lok handguard, Timney flat trigger, and one 35rd polymer magazine." canonical_url: "https://www.kygunco.com/product/sig-sauer-pmpx-4b-9-35-mpx-9mm-pistol-4.5-pcb-al-mlok-hg-35rd-black" meta: author: KYGUNCO "og:description": "Black 9mm MPX K with a 4.5\" barrel, PCB folding brace, gas-piston operation, M-Lok handguard, Timney flat trigger, and one 35rd polymer magazine." "og:image": "https://cdn.kygunco.com/assets/products/216200/thumbnail.jpg?v=1761851081" "og:image:height": "500" "og:image:width": "500" "og:title": "Sig Sauer MPX K Black 9mm Folding Brace" --- > Index of every page on this site: [llms.txt](https://www.kygunco.com/llms.txt) [Home](https://www.kygunco.com/) / [Shooting](https://www.kygunco.com/category/shooting) / [Guns](https://www.kygunco.com/category/shooting/guns) / [Handguns](https://www.kygunco.com/category/shooting/guns/handguns) / [Semi-Auto](https://www.kygunco.com/category/shooting/guns/handguns/semi-auto) / SGS-PMPX-4B-9-35 ![Main product image](https://static.kygunco.com/cdn-cgi/image/f=auto,w=600/assets/products/216200/main.jpg?v=1761851081) For illustration purposes only, this image may not be an exact representation of the product. # SIG SAUER MPX K 9mm 4.5" 35rd w/ PCB Folding Brace - Black The SIG SAUER MPX K is a new 9mm firearm with a 4.5" barrel, gas-piston operating system, and black hard-coat anodized receiver. It features a PCB folding brace, M-Lok alloy handguard, Timney flat trigger, and suppressor-ready M13.5 x 1mm threads. One 35-round polymer magazine is included. 5.0 ** ** ** ** ** [3 reviews](#reviews) $2,199.99 ** 5 interest-free payments of **$440** with ![Sezzle logo](https://www.kygunco.com/brands/sezzle.svg) ** ![Credova logo](https://www.kygunco.com/brands/credova.svg) As low as **$208.03**/month with ![Credova text logo](https://www.kygunco.com/brands/credova-text.svg) ** Online In Store ** Free Shipping Enjoy delivery to the Lower 48 States at no cost. ** Ships To FFL Dealer Handled by our expert shippers in Bardstown, KY. ** Check Local Restrictions Not sure whether this item can be shipped to your area? Enter your ZIP code for a quick check. Selling fast. Limited quantities available. Item # 216200 Style PMPX-4B-9-35 UPC 798681666744 Condition New Manufacturer [Sig Sauer](https://www.kygunco.com/brand/sig-sauer) Model MPX K Hand Right Hand Finish Black Round Capacity 35 Caliber 9mm Action Semi-Auto Barrel Length 4.5 in Trusted by professionals around the globe, the MPX K from SIG SAUER delivers exceptional reliability and durability through its closed-bolt gas piston system. Like all MPX models, the K is fully modular, supporting various handguard and barrel configurations and is suppressor-ready right out of the box. The latest iteration of the MPX K includes the SIG PCB folding brace, enabling the firearm to fold into a compact form while remaining fully operable in the folded position. It also features an upgraded M-Lok handguard, available in multiple lengths to accommodate suppressor coverage. Enhancing performance further, the MPX K now comes equipped with the ultra-smooth, lightning-fast Timney Trigger—co-developed by Timney and SIG. This trigger combines Timney’s renowned precision with the rugged reliability required for sub-gun platforms. For those seeking the pinnacle of modular sub-gun design, the MPX K stands out as the ultimate choice. - Height: 8 in - Overall Width: 2.4 in - Twist Rate: 1:10 - Weight: 5 lbs - Operating System: Gas Piston - Barrel Material: Carbon Steel - Threads: M13.5 x 1mm - Stock Type: PCB - Grip Type: Polymer - Trigger Shape: Flat - Forend Type: Alloy - Accessory Rail: M-Lok - Mag Type: MPX - Mags Included: (1) 35-Round Polymer Mag - Receiver FInish: Hard Coat Anodized ** WARNING: This product contains chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, go to [www.p65warnings.ca.gov](https://www.p65warnings.ca.gov). 5.0 ** ** ** ** ** 3 reviews ** ** ** ** ** 3 ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ## Reviews ** Verified Customer Not shot the pistol yet due to work, but the customer service was great! No waiting around for someone to notice you like "buds". An hours travel but worth it 7 months ago ** ** ** ** ** ** Verified Customer Really easy, first time buying a firearm online. 9/10/2025 ** ** ** ** ** ** Verified Customer Great Price, Fast shipping, Thanks! 9/9/2025 ** ** ** ** ** ## Don't Forget Your Ammo ```json {"@context":"https://schema.org","@graph":[{"@id":"https://www.kygunco.com/#website","@type":"WebSite","description":"Shop KYGUNCO for firearms, ammo, accessories, parts, and outdoor gear at low prices with fast, easy nationwide shipping.","name":"KYGUNCO","url":"https://www.kygunco.com/","publisher":{"@id":"https://www.kygunco.com/#/schema/organization/kygunco"}},{"@id":"https://www.kygunco.com/product/sig-sauer-pmpx-4b-9-35-mpx-9mm-pistol-4.5-pcb-al-mlok-hg-35rd-black#webpage","@type":"WebPage","description":"Black 9mm MPX K with a 4.5\" barrel, PCB folding brace, gas-piston operation, M-Lok handguard, Timney flat trigger, and one 35rd polymer magazine.","name":"Sig Sauer MPX K Black 9mm Folding 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