Product Glossary

ATC Truck Covers Product Glossary

(Listed in alphabetical order)


Third / 3rd Brake Lights

Also called a “CHMSL” (Center High Mounted Stop Light). Built into every ATC truck cap for models built after 1995. This third brake light is a required by law on all 1996 and newer trucks.


A T-handle is a handle that is shaped like the letter "T”. This design makes it easy to open, close and lock. Two T-handles (on one each lower corner) are typically considered to be more secure than a door with a single T handle that uses cables or rods to secure the cargo area.

12 Volt / Battery Dome

All ATC truck toppers have a 12-volt interior light or battery operated dome light included at no charge.

4-Bar / Scissor Hinge

Our 4-bar hinge, also called a scissor hinge, lifts a truck lid / tonneau cover up and away from the cab of the truck. This is essential on some newer body style trucks that have forward swept bed sides, or a curved front bed rail (bulkhead rail right behind the cab). Without this custom hinge system, many lids would have the front corners dip down when the rear of the lid is lifted up. This could cause the front tips of the lid to come in contact with the side of the bed. Consider purchasing an ATC tonneau cover that uses this hinge system to protect your truck and give you the best fitting lid possible.

Base Coat

The first coat of color (paint) that goes into your cap. Just like your truck is painted, we use a base coat of color and then a clear coat for the shine. ATC uses proudly uses PPG paints and materials for a top of the line finish.

Bed System

A unique cargo management system that acts as a full-length drawer for the bed of your truck. Once it’s mounted in your bed with our no-drill system, it’s like having your bed slide out to the rear of the truck to put things that were in the front of your bed within easy reach. As the only sliding cargo drawer on the market with the easiest installation, ATC is convinced you’ll love it once you try it.

Carpet / Carpeted Headliner

This fabric liner, sometimes called a “Foss” liner is a non-absorbing fabric made from a durable polypropylene that feels like carpet, has a charcoal grey to black tint, and won’t mildew or mold. It makes the underside of any truck cap or lid look like the best looking truck cap or best looking lid on the market. In addition to adding a finished look to the underside, this “carpet” also minimizes getting fiberglass splinters in your fingers when you touch the underside. This is one accessory that is an affordable option if you choose it when your cap or lid is being built. Adding it later can be very costly.

Clear Coat

This is what makes the finish on your truck cap or tonneau cover shine!

Closed Mold

One of our two processes to build truck parts. While not all parts can be built with this process, closed molding production allows us to produce more parts, in the most consistent quality possible, in the shortest amount of time with fewer people and is both stronger and lighter weight. The process is similar to an injection mold or vacuum mold using a CCBM (closed cavity bag molding) method.

Clothes Hanger

This is what you hang your clothes on inside a truck cab.

Double Bulb Seal / Rubber Bottom Seal

A rubber bottom seal, also known as a double bulb seal, goes underneath the rail of the truck cap or camper shell and is what makes contact with the top of the truck bed. Shaped like a letter “B” on its side, it offers two bulbs or barriers to keep moisture and other elements out of your bed. It’s made of rubber, which doesn’t break down or wear out as fast as foam can. It also protects your truck bed somewhat better than the basic foam seal.

Drop / Flip / Fold Down Window: Picture Or Slider

Same as a picture window or slider except a drop down / fold down version has a hinge along the bottom of the window frame and release pins at the top. This makes it easy to clean the glass between the bed and the cab. When the window folds down into the truck bed, you have access to the exterior side of the window, as well as access to the back of the cab. Please consider this option for long term satisfaction.


The inside area of a truck cap, along the bottom edge that is parallel to the truck bed rail. An ATC flange is applied by hand and also wraps over toward the inside edge of the bed just slightly for a clean look.

Foam Seal

A basic, closed cell (non-absorbing) foam seal about 2-3″ wide that goes on the bottom of your truck cap to protect the top of your truck bed. This is typically a dealer installed item and isn’t supplied or offered by ATC.

Front Slider / Sliding Window

A front window in a truck cap that slides open to allow some air to flow into the bed compartment. If the truck itself has a rear sliding window, it helps to have a slider in the cap, too. This makes it possible to haul longer items (use caution) or to pass something from the truck to the bed without getting out of the truck.

Gel Coat

The first barrier coat that is sprayed into the mold. This provides a primer type finish to apply the base coat of paint to.

Hand Laid Fiberglass

Portions of our process involve laying woven pieces of fiberglass mat into the unit due to its shape or when needed in areas for reinforcement.

Honeycomb Insulated Roof

A reinforcing material that ATC adds to ALL of their truck caps to provide extra strength and rigidity making them one of the strongest truck caps you can buy.

Lift Assist Arms

Many of our lids have a system that helps make it easier to open the lid with just one hand. Our lift assist product also takes the continuous pressure from the gas shocks and applies it to the lift assist arm, instead of putting pressure on your truck bed. Lift assists make it much easier to open and close your cover.

Open Mold

The way most fiberglass parts are built today and have been for 40 years. Fiberglass is hand sprayed into a mold that is open to room and is basically built by hand taking anywhere from 5-20 people during the lamination process alone.

Oversized Window Or Door

A taller than normal side window or door for additional visibility, and better looks on today’s contemporary trucks.

Painted Trim

Narrow vinyl trim that goes around the bottom edge of a truck cap or tonneau cover to give it a finished look. This trim gets painted just like the rest of the unit.

Picture Window

The front window in a truck cap / camper shell that is a solid piece of automotive glass and does not open. This style offers better visibility over a slider since there is no “seam” breaking up your vision at the rear of the cab.

Rotary Latch / Slam Latch

This type of latch lets you shut your lid or door just like a car door. Push it shut and it’s latched.

Sliding Side Windows

ATC uses 1/3 sliding windows on the sides of all our truck caps. Some of our competitors still use 1/2 sliders, but don’t be fooled by thinking they are better. While ½ sliders do open a few more inches, it usually puts the latch just out of reach without having to crawl into your truck on your hands and knees. Our 1/3 sliders are easy to use, easy to reach, and provide ample ventilation in almost any situation.

Solid Side

A solid truck cap is made with no side windows. Many fleet accounts like this style for privacy, and to easily create a “billboard” to market their business on. Some prefer this style for a custom / California look for their show truck. For this purpose, customers should know that while this side panel will have a nice, clean look, the fiberglass is not as flat and smooth as a large piece of glass or steel. A small bit of variation in how flat the sides look should be expected.

Strut / Shock / Lift Assist / Shocks

These have many names. They look like skinny little shock absorbers, that hold your doors and tonneau covers or lids open.

Truck Cap / Camper Shell / Canopy / Truck Top / Truck Topper

These are all the same thing. No matter how you slice it, ATC makes the best truck caps for your Ford, Chevy, Dodge, Toyota, Nissan or Mazda truck!

Vented Win-Door

This type of window is the same as a win-door, but has a small sliding window with a screen in it for ventilation.


This is a combination side window and door. It is a window that is hinged across the top to allow access to the bed or toolbox from the side of the truck, but is made of automotive glass for visibility. Two “T” handles, one in each lower corner, latch and lock this shut when needed.




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ATC Truck Covers
801 E. North St.
Ottawa, KS 66067
Phone: 1-800-983-2787

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