ATP, Stoneguard, Anodized and Blackout: Exterior Trim Decoded
The exterior options list reads like a parts catalog. Here is what each trim term actually is and what it does for the trailer.
August 24, 2026 · 4 min read
Open the exterior section of our options list and you will find ATP stoneguard, anodized corners, cast aluminum corners, 24-inch ATP down the sides, and a blackout trim package. Every one of those is a real, useful part of the trailer, but the names assume you already know what they mean. This post translates them.
ATP
ATP is aluminum tread plate, the diamond-pattern sheet you see on toolboxes and truck bumpers. On a trailer it is used wherever the skin takes abuse: the front, the lower sides, the tongue and the fenders. It is thicker and far more dent-resistant than the smooth skin, and it hides scuffs. Black ATP is the same material powder coated black.
Stoneguard
The stoneguard is the panel of ATP across the lower front of the trailer, typically 24 inches tall. Its job is to take the gravel and road debris that the tow vehicle's rear tires throw at the front of the trailer at highway speed. Without it, the smooth front skin pits and chips within a few thousand miles. On a V-nose trailer the stoneguard wraps the V; the options list also offers ATP up the full V-nose for trailers that see a lot of gravel road. If the trailer will be towed regularly on the highway, order the stoneguard. It is one of the least expensive ways to keep the front looking new.
24-inch ATP down the sides
The same idea applied along the lower two feet of the side walls and rear. It takes the kicked-up gravel from the trailer's own tires, the bumps from carts and equipment being loaded, and the scrapes from tight jobsites. Landscaping and construction trailers benefit most. The options list offers it in ATP, anodized aluminum or colored metal, so you can match the look you want.
Corners: anodized, ATP or cast
The vertical corners of the trailer are trimmed with an extrusion that covers the seam where the skin meets. Standard is a plain aluminum corner. Anodized corners have a treated finish that resists dulling and corrosion. ATP corners are tread plate. Cast aluminum corners with an anodized insert are a heavier, more finished look for a flat-front trailer. For a trailer that lives near the coast, anodized holds up best; our post on humidity, rust and coastal trailers explains why.
The blackout trim package
The blackout package bundles the appearance items: black trim, black ATP stoneguard, black ATP up the V-nose, smooth black fenders and black spoke wheels. On a black or charcoal trailer it produces the all-dark look that has become the most popular appearance spec on our lot. It is a look, not a protection upgrade, though the stoneguard and ATP inside the package do their normal job. Pair it with a screwless exterior and one of the darker Poly-Cor colors for the full effect.
Smaller trim items worth knowing
- 3-inch bottom trim: a taller strip along the bottom edge; standard on 8.5-wides.
- Red and white reflector tape: conspicuity tape along the sides and rear, required on some commercial trailers and sensible on any dark one.
- Covered tongue: plywood and ATP over the tongue frame, useful for a toolbox or generator platform.
For a working trailer, the practical order is stoneguard first, side ATP second, corners third, and blackout only if you care how it looks. When you spec a custom build, tell us where the trailer will run and we will point you at the trim that earns its cost.
Frequently Asked
Is the stoneguard standard?+
It is an option on most builds. Given what it protects, most buyers who tow on the highway order it.
Does the blackout package protect the trailer?+
The stoneguard and ATP inside it do. The rest of the package, black trim, fenders and wheels, is appearance.
Can I add ATP later?+
The stoneguard and side ATP can be added after delivery, though it is more work than ordering it at build time. Corners and trim are best specified up front.
Does ATP need any maintenance?+
Very little. Wash it with the rest of the trailer and it holds up for years. Black powder-coated ATP can show scratches down to the bare aluminum, so a touch-up on the stoneguard now and then keeps it looking right. Anodized corners should not be scrubbed with anything abrasive.
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