Free Shipping & Free Returns*

FREE SHIPPING on Over 250,000 Products

Shop now and get Free Value Shipping on most orders over $49 to the contiguous 48 states, DC, and to all U.S. Military APO/FPO/DPO addresses.

Enjoy our FREE RETURNS

We want to ensure that making a return is as easy and hassle-free as possible! If for any reason you are not satisfied with your purchase, simply return the item within 30 days of receipt, and we'll cover the cost of return shipping. Learn more about our Return Policy.

Shopping Cart
Special offer available for this product. Click here to see!
Government Export Restriction Government Export Restriction
Questions & Answers
What makes this incompatible with Armaspec Silent Capture?

An extension plug goes into the BCG. The plug would keep the BCG from cycling because the rod on the silent capture would have nowhere to go since it normally gets pushed into the back opening of the BCG as it cycles.

by Steve, Verified Owner, February 11, 2025
I want the one that folds away from the ejection port, which one should I order?

You want left hand fold

by Derek, Verified Owner, April 7, 2025
Customer Reviews
Helpful Positive Review Sylvan gen4 stock by Northwoods, Verified Owner, October 11, 2024
Thing works great! Thought about a law tactical but couldn't just the cost on my 8.6 blackout build. Easy install and an ar10 aero lower and works seemlessly with the ar10 bolt. Highly recommend in general, but especially for the price.
2/2 found this helpful
Helpful Positive Review Folding stock adapter by sylvan arms by ghettyup, Verified Owner, October 28, 2024
Glad I made this purchase. If you’re stuck between this folding stock adapter and the other guys, go ahead and give it a try you won’t be disappointed. I was very hesitant at first but glad I pulled the trigger ( no pun intended) . Great product at a...
Read More...
2/2 found this helpful
Helpful Positive Review Decent - but you might want to be handy - and have some inclination on how things work - by Don Bosell, Verified Owner, November 5, 2024
Product came - ZERO instructions - I mean ZERO - Sooooo.........watch a utube video if you can locate one - otherwise you - are on your own on how to figure out on installing it - It did come with a castle nut tool - so that was somewhat of a bonus -...
Read More...
1/1 found this helpful
Helpful Positive Review Very happy! by Pogogh, Verified Owner, December 3, 2024
I have watched several videos and reviews, decided to go with SA and was not disappointed. Very easy to install. Good retention and great fit.
1/1 found this helpful
Helpful Positive Review Worth It!! by Cam, December 10, 2024
Great product, function's as it should,easy install, comes with everything you need ,even a scan code for install video!! AWESOME
2/2 found this helpful
Helpful Positive Review EASIEST INSTALL EVER by jack, Verified Owner, April 27, 2025
Being retired and on a budget I made the mistake of ordering a “knock off" from China. As a matter of fact I ordered two of them. Found the ‘Real Deal" on Optics Planet and could not be happier. This product is so well thought out it's amazing. The...
Read More...
1/1 found this helpful
Read All 59 Reviews
In Stock
2 Models Available
Additional Features
All
Search

Product Info for Sylvan Arms AR15 & AR9 Gen 4 Folding Stock Adapter

The Sylvan Arms Folding Stock Adapter allows you to fold your stock and significantly reduce the length of your rifle for easy stow and travel.image

The Gen 4 AR Folding Adapter sits closer to your AR lower to reduce the length and any gaps. Turn your rifle into a foldable AR providing a compact rifle setup.

The direction of the fold is orientated to the direction as if your build was pointed down range. On a standard build, Folding to the RIGHT folds toward the ejection port. Folding to the LEFT folds off to the side with out the ejection port. Our previous folders have folded off to the LEFT.

  • Fit: Platforms .223/5.56 to .308 & Most 9mm
  • Does NOT work with Tippmann 22 or LWRC Pistols
  • Some 9mm bolt carriers with standard sizing, 5/8 ID (.625) can use the included bolt extension after removing the pin and weight from the back of the BCG
  • Compatible with your 300 Blackout AR’s for an effortless 300 Blackout Folding Stock Setup
  • If your bolt carrier group is causing the bolt extension to come up short contact us for a conversion. 
  • Includes all items needed to install.

Specifications for Sylvan Arms AR15 & AR9 Gen 4 Folding Stock Adapter:

Manufacturer: Sylvan Arms
Condition: New
Color: Black
Gun Make: AR Platform
Fabric/Material: 7075 Aluminum
Threads per Inch: 1-3/16x16
Weight: 6 oz

Features of Sylvan Arms AR15 Gen 4 Folding Stock Adapter

  • Now Available as a left or right fold, pick the best AR side folder setup to fit your needs.
  • Compatible with most AR15
  • Standard 1-3/16 x 16 thread and does not require any additional parts to be used with standard AR15 Bolt Carrier Groups.
  • CNC-machined from 7075 Billet Aluminum, making it uniquely lightweight and corrosion-resistant. This assembly weighs only 6.0 ounces.
  • The included wrench makes for a quick and easy install. The product does not need to be disassembled in order to install it onto your rifle/pistol.
  • Simply screw on, fold and carry!

Package Contents:

  • Sylvan Arms AR15 Gen 4 Folding Stock Adapter
  • .625 Aluminum Bolt Extension
  • Castle nut wrench

Sylvan Arms AR15 & AR9 Gen 4 Folding Stock Adapter Orderable Models

List of Orderable Models

Sylvan Arms AR15 & AR9 Folding Stock Adapter, Gen 4, Left Fold, Black, ARH400-L , MPN: ARH400-L , UPC: 811313033353 , Code: 46S-STA-FSTA-ARH400-L
Sylvan Arms AR15 & AR9 Folding Stock Adapter, Gen 4, Right Fold, Black, ARH400-R , MPN: ARH400-R , UPC: 811313033360 , Code: 46S-STA-FSTA-ARH400-R

Sylvan Arms AR15 & AR9 Gen 4 Folding Stock Adapter Unavailable & Discontinued Models

List of Unorderable Models

USED, Sylvan Arms AR15 & AR9 Folding Stock Adapter, Gen 4, Right Fold, Black, ARH400-R , MPN: ARH400-R-EDEMO , Code: 46S-STA-FSTA-ARH400-R-EDEMO-IN-C
DEMO, Sylvan Arms AR15 Folding Stock Adapter, Gen 4, Right Fold, Black, ARH400-R , MPN: ARH400-R-DEMO , Code: 46S-STA-FSTA-ARH400-R-DEMO
USED Sylvan Arms AR15 Folding Stock Adapter, Gen 4, Right Fold, Black, ARH400-R, EDEMO1, Used, Condition Fair , MPN: ARH400-R-EDEMO1 , Code: 46S-STA-FSTA-ARH400-R-EDEMO1
USED Sylvan Arms AR15 Folding Stock Adapter, Gen 4, Left Fold, Black, ARH400-L, EDEMO1, Condition Fair, Other , MPN: ARH400-L-EDEMO1 , Code: 46S-STA-FSTA-ARH400-L-EDEMO-OT-D
USED, Sylvan Arms AR15 & AR9 Folding Stock Adapter, Gen 4, Right Fold, Black, ARH400-R , MPN: ARH400-R-EDEMO , Code: 46S-STA-FSTA-ARH400-R-EDEMO-DF-F
Compare (0)