Buy SI Online
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 (2,384)
Sig Sauer W1911XCA-45-BXR3-RXX 1911 X Carry 45 ACP 4.25" Black DLC Pistol
Sig Sauer SORX1490 24MM 6MOA Green Dot Reflex Sight
Sig Sauer Electro-Optics SORX1480 Romeo-X Enclosed Compact Black 1x24mm 3MOA Green Dot Reticle RX Footprint Mount
Sig Sauer Electro-Optics SORX1390 Romeo-X Enclosed Pro Black 1x24mm 6MOA Green Dot Reticle RX Footprint Mount
Sig Sauer Electro-Optics SORX1380 Romeo-X Enclosed Pro Black 1x24mm 3MOA Green Dot Reticle RX Footprint Mount
Sig SAUER ROMEO-X 6MOA GREEN DOT BLACK
Sig Sauer SORX1090 24MM Black Optics Ready Red Dot
Sig Sauer SORX1030 ROMEO-X Reflex Sight 1x24mm 3MOA Black
Sig SAUER SOR02160 Romeo-RS 6 MOA Red Dot Sight Black Compact
SIG SAUER SOR02100 Romeo-RS Black Compact Circle Dot Sight
Sig SAUER Romeo-RS Pro 6 MOA Black Pistol Red Dot Sight (SOR02060)
SIG SAUER SOR02000 Romeo-RS Black Pro Footprint Circle Dot Sight
Sig SAUER 320C-9-BSSP-MS-MA P320 Compact 9mm 3.9" Nitron Semi-Auto Pistol
Sig SAUER 365XCA-9-BXR3-MS-MA P365 X-MACRO 9mm 3.7" Nitron Semi-Auto Pistol
Sig SAUER SOZ40002 ZULU10 HDX Flat Dark Earth IPX7 Waterproof and Fogproof Multi-Coated HD Lenses SOZ40002
Sig SAUER SOZ40001 ZULU10 HDX Flat Dark Earth IPX7 Waterproof and Fogproof Multi-Coated HD Lenses SOZ40001
SIG Sauer Full-Size 9mm Luger 15rd Steel Mag SIGLITE Sights
Sig SAUER SOZ6WP1850M Zulu 6 HDX Pro OIS Image Stabilization SOZ6WP1850M
Sig Sauer SOZ6WP1850 Zulu6 HDX Pro 18x50mm Binoculars Flat Dark Earth
Sig Sauer SOZ6WP1650 Zulu6 HDX Pro 16x50mm Binoculars Flat Dark Earth
Sig Sauer SOZ6WP1450 Zulu6 HDX Pro 14x50mm Binoculars Flat Dark Earth
Sig Sauer MCX Spear 6.8X51 16" 20RD RSPEAR6816BNG
Sig SAUER P238 Two-Tone 380 ACP 2.7in 6rd/7rd Mags Pistol 238-380-TXR3
Sig Sauer ECHO SOEC22100 1-8X25 Thermal Clip-On, 9+ Hr Runtime, Black
Sig Sauer SOEC12310 ECHO 2-16x50mm Thermal Sight with 1000y Rangefinder
ECHO SV 1.5-12x35mm Thermal Sight - High Precision Imaging Optic
Sig Sauer W365F-9-BXR3P-RXX P365 9mm 4.3" Black Semi-Auto Pistol
Sig Sauer W365F-9-BXR3P-MS P365 9mm 4.3" Nitron Semi-Auto Pistol
Sig Sauer SOTD62112 TANGO DMR 2-12X FFP Rifle Scope, MRAD Reticle, 42mm
Sig Sauer SOTD62111 TANGO DMR Rifle Scope 2-12X FFP MOA Reticle 42mm Black
Sig Sauer W1911XR-45-BXR3-RXX 1911 X Series .45 ACP 5" Black DLC Pistol
SIG SORX1408 ROMEO-X Reflex Sight Enclosed CMP Rose
Sig Sauer SORX1402 Romeo-X 1x24mm Red Dot Black/Rose Gold 2 MOA Circle
ROMEO-X Enclosed Reflex Sight: High Precision Optics
Sig Sauer SORX1302 Romeo-X Enclosed Pro 6 MOA Red Dot FDE 1.83" 1.20 oz
ROMEO-X Enclosed Reflex Sight: High Precision Optics for Sharp Shooting
Sig Sauer SLX68-MG-QD-1 6.8mm Inconel Suppressor QDS 30-Round Capacity
Sig Sauer SOR30800 Romeo 3 MAX PRO 8 MOA Red Dot Matte Black
Sig Sauer SOR30300 Romeo3Max Pro 1x31mm 3 MOA Red Dot Sight Black
SIG SAUER 1911 8-Round 45 ACP Black Magazine - Mec-Gar 8901701
Sig Sauer SOR21601 Romeo2 1x30mm 6 MOA Red Dot Matte Black
Sig Sauer Romeo2 Mil-Spec Reflex Sight 1x 30mm 3 MOA Red Dot Adjustable ...
Sig Sauer SOZBH103 Zulu Binocular Harness FDE Medium, Enclosed Design
Sig Sauer W365F-9-BXR3P P365 9mm 4.3" Nitron Semi-Auto Pistol
Sig Sauer SIGM400 5.56 NATO 30+1 Cerakote Moss Green 16" Rifle
Sig SAUER CROSS 798681700783 7MM PRC Rifle, Carbon Fiber Barrel, Moss Green
SIG Sauer CROSS 300 WM Rifle 6+1, Carbon Fiber Barrel, Moss Green
Sig Sauer CROSS Multi Caliber 300 PRC 24" Bolt Action Rifle 6-Rounds
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...
Ready to Shop SI?
Choose SI for straightforward, well-engineered accessories that improve usability and durability without unnecessary complexity....
Browse All Products