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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 TANGO SOTMC61000 1-6x24 30mm Tube Illuminated BDC Reticle
Sig SAUER P320 X-Carry 9mm 3.9in 2x10rd Black Striker Fired Pistol
Sig SAUER 320XCA-9-BXR3P-R2 P320 X-Carry 9mm 3.9" Nitron Semi-Auto Pistol
Sig SAUER INC P365 Fuse Romeo-RS Compac 9MM LUGER (2) 21+1 & (1) 17+1 4.3 Nitron
Sig SAUER 365X-9-BXR3P-RS P365X ROMEO RS 9mm 3.1" Nitron Semi-Auto Pistol
Sig SAUER 365-9-BXR3P-RS P365 RS 9mm 3.1" Nitron Semi-Auto Pistol
Sig P320 XFULL 9MM 4.7" ROMEO- RS PRO (2)17RD X-GRIP
Sig P320X COMPACT 9MM 3.6" ROMEO-RS PRO (2)15RD XGRIP
Sig SAUER 320C-9-BSSP-RS P320 Compact RS 9mm 3.9" Nitron Semi-Auto Pistol
Sig Sauer P365 XMACRO Kit 9mm Luger 10rd Magazines(2) 3.7 Barrel Dummy Rounds Certificate for LifePod
Sig Sauer P365 XMACRO Kit 9mm Luger 17rd Magazines(3) 3.7 Barrel Dummy Rounds Certificate for LifePod
Sig Sauer SIGM400 Rose 5.56 NATO 30+1 Magpul SL Stock Romeo5 Gen II
Sig Sauer Romeo MSR Gen II 20mm Red Dot Sight 2 MOA Flat Dark Earth
Sig SAUER Romeo5 Gen II 1x20mm Rifle Red Dot Sight (SOR5111)
Sig Sauer W320F-40-BXR3-PRO-RXE P320 40 S&W 4.7" Nitron Semi-Auto Pistol
Sig Sauer W320CA-40-BXR3-PRO-RXE P320 Carry Pro 40 S&W 3.9" Nitron Pistol
Sig SAUER P322 .22LR 4in 2x20rd Coyote Pistol with Manual Safety (322C-CAS)
Sig Sauer Electro-Optics SORX1560 Romeo-X Sig-Loc Pro Black Cerakote 1x ...
Sig Sauer Electro-Optics SORX1530 Romeo-X Sig-Loc Pro Black Cerakote 1x ...
Sig Sauer SORX1500 ROMEO-X 2MOA Circle/Dot Reticle Matte Black
Sig SAUER M18 CSS 9mm 3.9in 10rd Coyote Striker Pistol (M18-9-CSS-MS-10)
SIG M18-9-CSS-MS 9mm 3.9" Coyote PVD Optic Ready 17+1/21+1 Mags
SIG M17-9-CSS-MS-10 9mm 4.7" Coyote PVD Optic Ready 10+1 3 Mags
SIG M17-9-CSS-MS 9mm Pistol, 4.7" Barrel, Coyote PVD, Optic Ready
Sig Sauer Zulu 6 HDX OIS Image Stabilization Orange
Sig Sauer Zulu 6 HDX Image Stabilization Binoculars Orange
Sig SAUER 322C-B-RS P322 22 LR 4" Nitron Semi-Auto Pistol
Sig ECHO CV MOUNT QR 1.93" BOBRO BLK
Sig ECHO CV MOUNT QR 1.70" BOBRO BLK
Sig ECHO CV MOUNT QR 1.535" BOBRO BK
Sig Sauer SORJ8T101 Romeo8T 1x40mm Quad Ballistic Circle Dot Matte Black
Sig Sauer Romeo8T 1x40mm Quad Ballistic Circle Dot 2.0 Reticle Red S...
Sig Sauer WRSPEAR-HYP-68-16B MCX Spear 6.8x51mm 16" Coyote Rifle
Sig Sauer 320XF-9-MAXM-10 P320 9mm 3.9" Matte Black DLC Pistol
Sig Sauer 320XF9MAXM P320 9mm 3.9" Matte Black DLC Semi-Auto Pistol
Sig Sauer 320XCA-10-COMP-MS-10 P320 XTEN 10mm 3.8" Nitron Pistol 10rd
Sig Sauer 320XCA-10-COMP-MS P320 XTEN 10mm 3.8" Nitron Pistol 15rd
Sig Sauer 320X5-10-BXR3-R2-MS-10 P320 XTEN 10mm 5" Nitron Pistol 10rd
Sig Sauer 320X5-10-BXR3-R2-MS P320 XTEN 10mm 5" Nitron Pistol 15rd
Sig SAUER Romeo-X SIG-LOC Compact 6 MOA Red Dot Reflex Sight (SORX1660)
Sig Sauer SORX1630 ROMEO-X 3 MOA Dot SIG-LOC Matte Black
Sig Sauer SOR5X171 2 MOA Red Dot Black M1913 Rail
Sig Sauer W365XL-9-BXR3P-RXE P365 XL 9mm 3.7" Nitron Semi-Auto Pistol
Sig Sauer P365 9mm 3.1 Inch NITRON Striker Fired Compact Handgun
Sig Sauer W320F-9-BXR3-PRO-RXE P320 9mm 4.7" Nitron Semi-Auto Pistol
Sig Sauer W320CA-9-BXR3-PRO-RXE P320 Carry Pro 9mm 3.9" Nitron Pistol
Sig Sauer P320 Pro 9mm 15 Rounds with ROMEO-X Reflex Sight
Sig Sauer SOTS46000 TANGO 6-24x52 MOA BDC1 Reticle SFP Scope Black
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 W365XL-9-BXR3P-MS P365 XL 9mm 3.7" Nitron Semi-Aut
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
Sierra Bullets 4540C 7mm 0.284 Caliber 140 Grain Tipped Boat
SilencerCo AC1278 ASR Black Nitride 9/16"x24 LH Threads 30 C
Sig Sauer W365XL-9-BXR3P-RXX P365 XL Romeo-X 9mm 3.7" Nitron
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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Choose SI for straightforward, well-engineered accessories that improve usability and durability without unnecessary complexity....
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