K-TEC GUTTER SUPPLY K-TEC 5 Inch Musket Brown K-Style Aluminum Rain Gutter End Caps

Overview

Replacing a leaking gutter end cap is a 20-minute job—if the parts actually fit. I picked up these K-TEC end caps for a 5-inch K‑style aluminum run on my garage, hoping for a straightforward swap. The short version: they fit as expected, seat cleanly with sealant, and the musket brown finish blended in well with my existing system. There are a couple of small caveats—mostly about compatibility and installation choices—but overall the caps do exactly what they’re supposed to do: close the run and keep water on the right side of the fascia.

Design and build

These are standard aluminum end caps designed for 5-inch K‑style gutters. The “5-inch” spec refers to the front-to-back measurement across the mouth of the gutter, not the height, which aligns with how most gutter components are sized. The caps come as a pair, one left and one right, formed to match the K‑profile. The bends are consistent and square, and the surfaces arrived free of dings or warping. They feel like typical aftermarket thickness—not flimsy, but not overbuilt—so they form nicely around the gutter lip without needing excessive force.

The musket brown finish is even, with a consistent sheen. On my install, the color matched my existing musket brown gutter runs closely enough that I couldn’t spot a difference from the driveway; at arm’s length, there’s a slight variance in gloss under direct sun, which I expect with any mix of new and weathered paint.

There’s nothing exotic here—no built-in gaskets or pre-applied sealant. You’ll supply your own gutter sealant and, optionally, fasteners if you prefer a mechanical connection. That’s fine by me; I’d rather choose a sealant I trust than be locked into a thin factory bead.

Fit and compatibility

The contour matches a standard 5-inch K‑style aluminum profile well. The cap engaged the front lip and back wall without fighting me, and the corners aligned with the gutter’s bead. If your existing gutters are a different manufacturer with a slightly different K‑profile, you might have minor gaps at the inside corners—that’s typical with aftermarket caps. A flexible tripolymer or butyl gutter sealant will bridge small variances.

Important: check that you truly have 5-inch K‑style. That 5-inch measurement is across the opening of the gutter (front to back), not the height of the back wall. If you own 6-inch gutters, these won’t fit. Also, these are intended for aluminum systems; I wouldn’t pair them with copper gutters (galvanic corrosion risk), and I’d be cautious with uncoated steel. For mixed metals, use isolating sealant and avoid direct metal-to-metal contact.

You get both a left and a right. That’s convenient if you’re finishing a new run or keeping spares, but if you only need a single replacement, you’ll end up with one extra. It’s not a dealbreaker, just something to note.

Installation experience

My install took about 15 minutes per side, including cleanup. Here’s what worked well:

• Prep: I squared the gutter end with snips and a file, then cleaned it thoroughly with mineral spirits to remove oxidation and grime. Dry metal is critical; don’t rush this part.
• Sealant: I used a dedicated gutter/roof sealant (a thick, paintable tripolymer). I laid a continuous bead along the inside of the cap where it will contact the gutter’s front bead, bottom, and back wall, and a light bead along the outside seam for insurance.
• Seating: Starting at the front lip, I hooked the cap, then rolled it back into place. A few taps with a rubber mallet seated the bends. Squeeze-out is good; it means you have enough sealant.
• Securing: You can rely on the sealant alone if the fit is snug, but I prefer a mechanical hold. I added two aluminum pop rivets—one near the top back wall, one near the bottom—wiping excess sealant afterward.

After two heavy rains, there were no drips at the corners or underside. The cap stayed put, and the sealant line remained intact without splitting.

Durability and finish

It’s too early for a years-long verdict, but the baked finish (it appears to be a standard coil-coat) shrugged off installation scuffs, and the bends didn’t crack the paint. Aluminum end caps don’t rust, and with a good sealant, freeze/thaw shouldn’t open the seams. If you’re in a coastal environment, salt will age any finish faster, but aluminum remains a solid choice there compared to plain steel.

As always, the sealant is the weak link. Use a high-quality gutter sealant, not general-purpose silicone. Tripolymer or butyl-based products stay flexible and bond well to painted aluminum.

Value

For basic hardware that needs to fit, color-match, and not leak, these offer good value. Pricing was competitive with big-box equivalents, and the caps arrived quickly and undamaged. Since it’s sold as a pair, the per-cap price is reasonable, though single-side buyers might wish for individual options. Still, having a spare on hand isn’t the worst thing—you’ll use it eventually.

What I like

• Fit is true to a standard 5-inch K‑style profile; seats cleanly with minimal persuasion.
• Musket brown finish is a close match to common gutter colors.
• Clean stamping/bends without deformities, making for a predictable seal.
• Ships as a left/right pair, convenient for completing a run or keeping a spare.

What could be better

• No single-side purchase option; you’ll have an extra if you only need one.
• As with most aftermarket caps, slight profile variances across gutter brands mean your sealant choice and technique matter. Not an issue, but worth calling out.
• No sealant or fasteners included. I prefer choosing my own, but some DIYers might expect a kit.

Tips for a leak-free install

• Measure correctly: 5 inches is the opening width across the gutter, front to back.
• Dry fit first: Check alignment on the front bead and back wall before applying sealant.
• Use the right sealant: Tripolymer or butyl gutter sealant beats standard silicone. Apply a continuous bead inside the cap and tool the squeeze-out.
• Consider mechanical fastening: Two aluminum pop rivets or short stainless screws keep the cap from shifting with thermal expansion.
• Don’t over-hit it: Gentle taps with a rubber mallet are enough. Overdriving can kink the profile and create gaps.
• Clean thoroughly: Oxidation and dirt are sealant killers. Wipe with a solvent and let it fully dry.

Who it’s for

• Homeowners replacing a damaged or leaky end cap on a 5-inch K‑style aluminum system.
• DIYers finishing a new run who want a color-matched musket brown end without a trip to the sheet metal shop.
• Pros who need a reliable, off-the-shelf pair with predictable fit for common 5-inch installs.

If you’re working with 6-inch gutters, copper systems, or non-K profiles (half-round or box), look elsewhere.

Final take

These K-TEC end caps do the simple job they’re supposed to do: they fit a standard 5-inch K‑style aluminum gutter, install without drama, and seal up tight when paired with the right sealant and a couple of rivets. The musket brown finish blends well with existing systems, and the overall build quality inspires confidence. I would have liked the option to buy a single side, but getting a left/right pair isn’t a bad value proposition—especially if you’re completing both ends or want a spare in the toolbox.

Recommendation: I recommend these for anyone needing a straightforward, color-matched end cap solution for 5-inch K‑style aluminum gutters. The fit and finish are solid, installation is beginner-friendly with basic tools, and the price makes sense. Use a quality gutter sealant, take your time with prep, and you’ll end up with a clean, leak-free termination that should hold up for seasons to come.