Holster Comparisons, Holster Wedge Guides

Cloudster Pillow + T.Rex Arms Sidecar 2.0: Compatibility & Setup

Posted on by Cloudster Pillow
Cloudster Pillow T.Rex Arms

Quick answer: Yes, the Cloudster Pillow works with the T.Rex Arms Sidecar; our customers run it on the Sidecar 2.0. It attaches with hook-and-loop to the body side of the holster, low toward the muzzle. T.Rex also sells its own IWB Holster Wedge: a small, hook-backed foam wedge in a Small and a Large. The Cloudster Pillow holster wedge lets you set the thickness yourself and have a fabric cover against your skin. For any Sidecar setup, the Deluxe or the Monster.

Cloudster Pillow T.Rex Arms
A white Cloudster Pillow wedge installed at the muzzle end of a topographic-pattern AIWB sidecar rig — red-dot Glock and integrated mag carrier, the wedge cushioning the wide body-side panel.

Does the Cloudster Pillow Fit T.Rex Arms Holsters?

Yes. The Sidecar is a 0.093″ Kydex appendix holster that carries a spare magazine (or another attachment) next to the gun, and the pillow mounts with hook-and-loop on the side that faces your body. Loop strips and an alcohol wipe come with the pillow, so you have what you need for the first install. Our customers run it on the Sidecar 2.0, including with a Glock 19 and an Aimpoint ACRO (see their reviews below).

T.Rex also makes the Raptor, a Kydex IWB holster without an attached mag carrier.

Cloudster Pillow vs. the T.REX IWB Holster Wedge

T.Rex Arms describes its wedge as “a small foam wedge that is used to fine-tune the comfort and concealment of your IWB holster.” The Cloudster Pillow is a fabric pillow filled with shredded cooling gel memory foam, and you set the thickness by adding or removing fill. Both attach with hook-and-loop. I have used all the other brands. After months of daily-carry testing, the Cloudster Pillow is the best holster wedge for all-day comfort, and here is why on a Sidecar.

T.REX IWB Holster Wedge Cloudster Pillow
Fill Foam, “similar material to that found in our plate backers” Shredded cooling gel memory foam
Cover None listed Bamboo (White), cotton blend (Dark), 100% cotton (Camo)
Thickness Fixed: 0.500″ (Small) or 0.650″ (Large) Adjustable: add or remove fill
Sizes Two: 2.17″ × 1.90″ and 2.37″ × 2.82″ Four: Mini 3.5″ × 3″ to Monster 6″ × 5.5″
Mounting Hook and loop; 2 adhesive loop squares included Hook-and-loop; Velcro strips included; any IWB or AIWB holster
Made in USA USA
Warranty / returns Lifetime warranty; returns within 60 days (domestic orders) Lifetime warranty; free 30-day returns

Fill and cover

T.Rex says its wedges are “made from a similar material to that found in our plate backers” and lists no cover. The Cloudster Pillow is shredded cooling gel memory foam inside a fabric cover: bamboo on the White, a cotton blend on the Dark and 100% cotton on the Camo.

Thickness and size

The T.Rex wedge comes in two fixed thicknesses, 0.500 inch for the Small and 0.650 inch for the Large, at 2.17 × 1.90 inches and 2.37 × 2.82 inches. The Cloudster Pillow has no fixed thickness: open the hook-and-loop closure and add or remove shredded memory foam. It comes in four sizes, from the Mini at 3.5 × 3 inches to the Monster at 6 × 5.5 inches, and the Monster is built for extra-wide sidecar rigs.

The Raptor Holster Backer is not a Sidecar option

For its Raptor holster, T.Rex sells a separate Raptor Holster Backer, “Constructed from Alcantara and Closed-Cell PE foam.” T.Rex states: “The Raptor Backer only works with the Raptor Holster. It will not work with the Sidecar.” The Cloudster Pillow attaches with hook-and-loop to any IWB or AIWB holster, including the Sidecar.

For the full side-by-side against other wedge makers, see the 2026 holster wedge comparison.

Which Cloudster Pillow Size for a T.Rex Arms Holster?

Your setup Size
T.Rex Sidecar (any gun, with the mag carrier or another attachment) Deluxe or Monster
Glock 19 Deluxe or Monster
Sig P365 (no light) Standard or Deluxe
Other micro and subcompact 9mms (Hellcat, Glock 43/43X, Shield, P365X) Standard or Deluxe
Full-size (Glock 17, P320 Full Size, M&P) Deluxe or Monster
Any gun with a weapon light Deluxe or Monster

Shop the sizes in this table:

The choice between the two sizes is yours. For larger body frames we recommend sizing up: a larger pillow can always be made to feel smaller by taking some fill out, but a smaller pillow can’t be made to feel bigger. Not sure? Tell us your gun, holster and carry position and we’ll help you compare the two.

You can also use our size finder.

How to Install a Cloudster Pillow on a T.Rex Arms Holster

  1. Unload and remove the gun from the holster.
  2. Clean the body side of the holster with the included alcohol wipe and let it dry.
  3. Stick the loop strip on the body side, starting low toward the muzzle end; adjust to taste, since there is no fixed spot.
  4. Press the pillow on, thicker part toward the muzzle. Our adhesive reaches full strength after 24 hours, so give it a day before heavy use if you can.
  5. Wear it and check standing, sitting and bending. The grip should tuck in, and the holster’s bottom edge should be cushioned instead of pressing into you.
  6. Tune the fill. More fill tips the grip in further; less fill is subtler. If it pokes when you sit, move it up toward the trigger guard. Our wedge placement guide has the details.

What T.Rex Arms Customers Are Saying

“This paired with a Trex Sidecar 2.0 and suspenders finally made AIWB doable for me. I’ve struggled with appendix for years, trying it here and there to see if I can make it work. I haven’t been able to make it work until now.”
— Simon F. — West Valley City, UT

“Glock 19 with Aimpoint Acro in the T.Rex Arms Sidecar 2.0. Most comfortable wedge around. Kicks the crap out of any of the competition. Has made the holster actually comfortable for everyday life.”
— Holden Z. — Bemidji, MN

“At the time I primarily carried in an tier 1 axis elite or the Trex sidecar 2.0. Having such a heavy setup that takes up a lot of real estate for me (5’7 145lbs) it can be tough to make that much equipment comfortable. The cloudster deluxe has made the experience a lot more bearable. … I would highly recommend the deluxe for sidecars especially.”
— Eric C. — Auburn Hills, MI

Frequently Asked Questions

Does T.Rex Arms make a holster wedge?

Yes: the T.REX IWB Holster Wedge, a foam wedge in a Small and a Large, with a hook backing and two adhesive loop squares. It isn’t in the Sidecar’s list of included parts; the Sidecar comes with a wing attachment and the T.REX IWB Adjustable Claw.

What size Cloudster Pillow for a T.Rex Sidecar?

The Deluxe or the Monster, whatever gun you carry in it.

Will it fit a Sidecar with a weapon light?

Yes, on the body side below the light. The Deluxe or the Monster covers a weapon light.

Does it work with a red dot?

Yes. Holden Z. runs a Glock 19 with an Aimpoint ACRO in his Sidecar 2.0 (review above). For any Sidecar: the Deluxe or the Monster.

Can I use the T.Rex claw and the Cloudster Pillow together?

Yes. The Sidecar comes with T.Rex’s adjustable claw; the pillow goes low on the body side toward the muzzle. Adjust one at a time so you can tell what each does.

Can I move it to another holster later?

Yes. Peel it off the hook-and-loop and use a new loop strip on the next holster; extra strips are sold separately.

Related Guides

Cloudster Pillow

Cloudster Pillow makes the Cloudster Pillow, an adjustable-fill holster pillow for IWB and appendix carry. Questions about anything on this page: cloudster@cloudsterpillow.com.