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SI designs rugged, user-focused firearm components and optics. They make accessories like slide plates, charging handles, barrel clamps, red dots, and shotgun parts.
All SI Products (2,381)
Sig Sauer M400 Tread Handstop Kit, M-Lok, Black
SIG Sauer M400 TREAD M-LOK Forward Grip Kit
Sig Sauer Tread Ambidextrous Charging Handle Black Aluminum
Sig Sauer Lens Cleaning Kit with Retractable
Sig Sauer SOA30007 Alpha3 34mm Scope Mount 20 MOA Black Anodized
Sig Sauer SOA30006 Alpha3 30mm Scope Mount 20 MOA Black Anodized
SIG Sauer Alpha3 Mount 34mm Black Steel Picatinny
Sig Sauer Alpha3 Scope Mount 30mm Black
Sig SAUER Alpha3 Scope Mount 30mm 1.375 7075-T6 TI Hardware Bk SOA30001
Sig SAUER ROMEO8T RED DOT SIGHT BALLISTIC CIRCLE DOT 0.5 MOA ADJ
Sig Sauer GRIP-MMS-CA-943-SM-COY P320/250 Carry Grip Module Coyote 9/40/357
Sig Sauer GRIP-MMS-CA-943-M-COY P320/250 Carry Grip Module Coyote 9/40/357
Sig Sauer P365 Air Pistol CO2 4.5mm 12rd Black
Sig Sauer P320C-CA Recoil Spring Assembly for P320 Compact and XCarry Mo...
BTI KIT-320-43 Recoil Spring 320 CMPT 40/357SG
Sig Sauer P365 Take Down Lever for Series Handguns
Sig Sauer E300H1-SBR-20 300BLK 120GR Solid Copper Ammo 20 Rounds
Sig Sauer P365 Slide Catch & Springs Kit Replacement Parts
Sig Sauer P365 Non-Textured Slide Cap Inc.
Sig Sauer Kit365recoilspring P365 Recoil Spring Assembly 9MM Luger
Sig Sauer KIT-365-MAG-RELEASE P365 Magazine Release Kit Black
Sig Sauer KIT365GRIPMODBLK P365 Black Polymer Grip Module
Sig Sauer P365 Factory Replacement Barrel 9mm Luger Steel Matte Black
Sig Sauer SOX10009 X-Ray3 Day/Night Suppressor Sight Set
Sig Sauer E9MMB136550 365 Elite 9mm FMJ 115 Gr 50 Rounds Ammo
Sig Sauer Elite Defense 365 9mm Luger 115gr V-Crown Jacketed Hollow Point (VJHP)
Sig Sauer Romeo8T Red Dot Sight 1x38mm 2 MOA Ballistic Circle Dot
Sig Sauer Romeo8H Red Dot Sight 1x38mm Ballistic Circle Dot
Sig Sauer E308B120 Elite Performance 308 Win 150 gr FMJ 2900 fps Ammo
Sig SAUER Juliet4 4x24mm FDE Reflex Sight Magnifier (SOJ41002)
Sig Sauer AIR-VIRTUS-22 .22 Cal Grey PCP Airgun 30Rd
SIG AIR-1911WTP-BB .177BB We The People CO2 Pistol
Sig Sauer Sierra3 BDX 6.5-20x52mm 30mm Tube Illuminated BDX-R1 Reticle
Sig Sauer SOSBDX33111 Sierra3 BDX 3.5-10x42mm Illuminated Riflescope
Sig Sauer ROMEO1 Black Shroud Kit SOR1SK001: Medium Size, New Condition
Sig Sauer SOA20003 Alpha 2 Scope Mount 34mm 1.53" Black 6061-T6 Aluminum
Sig Sauer SOA20001 Alpha2 30mm Scope Mount/Ring Combo Black Anodized
SIG Sauer Romeo4T 1x20 Red Dot Optic - Circle Dot, MOTAC, IPX-7, FDE
Sig Sauer P365 12rd Extended Magazine 9mm Luger
Sig Sauer P365 10 Round 9mm Magazine With Extension
Sig Sauer Mag365910 P365 Micro-Compact 9mm Luger 1
Sig Sauer 320X Medium Grip Module: Full 9mm, .40 Auto, .357 SIG - Black
Sig SAUER 320X Carry Grip Module Medium Black Synthetic - Upgrade for 9/40/357
Sig Sauer GRIPX5F943MBLK P320 X-Five Grip Module, Black, Medium, 9/40/357
SIG Sauer P226 MK25 9mm Pistol - Navy SEALs Sidearm
Sig Sauer SORJ53101 Romeo5 2 MOA Red Dot & Juliet3 3X Magnifier Black
Sig Sauer P938 9mm "3.00" 7-Rounds
Sig Sauer P226 Full Size Legion SAO 9mm Luger 4.40" 10+1 Gray Cerakote Black G10
About SI
Headquarters
Established
-
Country of Origin
USA
History & Heritage
SI began as an American aftermarket parts maker aimed at providing functional, affordable upgrades and accessories for shooters. Over time the brand expanded its offerings across pistol, rifle, and shotgun platforms, becoming known for practical designs and broad compatibility.
Notable Products
Popular items include charging handles, slide adapter plates, red dot sights, barrel clamps, and shotgun conversion components.
Why Choose SI?
Choose SI for straightforward, well-engineered accessories that improve usability and durability without unnecessary complexity.
Hot SI Items June 2026
Trending right now based on the last 30 days of TheGunDock orders + page views.
SilencerCo Sparrow 22 Rimfire Suppressor 22LR 5.08" Stainles
SIG SAUER 322C-ROSE-RS P322 Rose 22 LR 4" Black Anodize Semi
Sig Sauer Tango-MRS Compact Rifle Scope 1-6x24 30mm SFP BDC6
Sig Sauer Cross Sawtooth Rifle 6.5 PRC 22 inch Moss Green Fo
Sig Sauer W365XL-9-BXR3P-MS P365 XL 9mm 3.7" Nitron Semi-Aut
Sig Sauer 2401191R Picatinny Stock Adapter for AR-15, Alumin
Sig Sauer SORX1080 24MM Black Pro Optics Ready Sight
SIG SAUER E26R-9-BSS-FBZ P226 Full-Size 9mm 4.4" 2-Tone Bron
Shop SI Products
Sig SAUER MCX-SPEAR 6.8x51mm SBR 13in Semi-Auto Rifle RSPEAR
SilencerCo Sparrow 22 Rimfire Suppressor 22LR 5.08" Stainles
Sig Sauer P320 FLUX 9MM 3.9" 30RD Legion 320
Sig Sauer SLH300TIQD 300 Blackout Titanium Suppressor
SilencerCo Velos LBP 5.56 NATO/.223 4.76 In Low Back-Pressur
SIG SAUER MCX Spear SBR 7.62x51mm 13" Nitride NFA
Sig Sauer P365X Macro Tacops 9mm 3.7" 17rd Pistol
Sinclair INTERNATIONAL DIAL INDICATOR .001
Sig Sauer ROMEO1 Black Shroud Kit SOR1SK001: Medium Size, Ne
Sig Sauer 8900823 LTXG Grip Module Laser Engraved P320-X Car
Sig Sauer MCX-SPEAR LT AR Conversion Kit 5.56 NATO 11.5" Bla
Sig SAUER MCX 5.56 NATO 16in 30rd IR Cerakote FDE Rifle RMCX
SI News & Articles
Firearm Shipping Restrictions by State (2026 Update)
State-by-state guide to firearm and ammunition shipping for online buyers and FFL dealers. Current as of May 2026. Cover...
Damaged in Transit: How TheGunDock Handles Shipping Claims on Firearms and Ammo
When a firearm or ammo shipment arrives damaged, the claim process matters. TheGunDock walks through what to do, what we...
The Springfield KUNA: Roller-Delayed 9mm Pistol That's Shaking Up the PDW Market
The Springfield Armory KUNA — a roller-delayed 9mm pistol built in partnership with Croatia's HS Produkt — has becom...
The Strait of Hormuz: 2,500 Years of Trade, Arms, and Conflict
A twenty-one-mile-wide choke point has shaped the movement of goods — and weapons — across half the ancient and mode...
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