


ATB A-SB51S Aluminum Step Saddle Boot Box, Single Top Hinged Lid, Pro-Grip Strut Steps
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- No Sales TaxZero sales tax on every order
- 30-Day Money-Back GuaranteeReturn it within 30 days of delivery for a refund

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Features
- Pro-Grip Strut Steps: Integrated Pro-Grip strut steps give non-slip footing, so the box doubles as a safe step up to the cab or deck.
- Single Top Hinged Lid: A single lid hinges at the top and opens the whole box from above; the top-hinged design helps shed water.
- Stainless Dolphin Tail Lock: A stainless steel dolphin tail T-handle lock comes factory installed by ATB on its aluminum saddle boxes.
- Seam Welded, Gusseted Corners: Seam welds and gusseted, reinforced corners give the box the extra heavy duty build ATB calls for on a semi.
- Smooth Aluminum Finish: The aluminum body has a smooth bright finish that matches polished semi-truck equipment.
- Four Mounting Kit Options: ATB offers four mounting kits, sold separately, rated from 300 lb to 500 lb depending on how the box attaches to the frame.
Description & Fitment
The ATB A-SB51S is an aluminum step saddle boot box for semi-trucks with a single top hinged lid and integrated Pro-Grip strut steps. It gives you a non-slip step and lockable saddle storage in one, secured by a factory installed stainless steel dolphin tail T-handle lock. The smooth bright aluminum body is seam welded with gusseted corners, and it is made in Blanchard, North Dakota.
Fitment & Compatibility
How to choose: every size is 25" tall and 28" deep, so measure the open length on the frame where the box will saddle mount and pick a width from 12" to 48".
Choose the mounting kit separately: M2100C (up to 500 lb), M3000C, M3000H or M3050C (each up to 300 lb).
Prefer a lid that drops open toward you? See the A-SB51S drop open lid version.
Fits: Semi-truck frames, saddle mounted (measure the frame space; see the size table)
About ATB
American Truckboxes (ATB) builds aluminum and steel truck boxes, tanks and storage in Blanchard, North Dakota, and has done so for more than 25 years, by its own account. Its range covers pickup crossover, side-mount, chest and drawer boxes, service-truck boxes and packs, fuel tanks, and heavy-truck and trailer boxes.
Authorized ATB dealer. Prestige Truck is an authorized ATB dealer: every box on this page is built by ATB to the part number shown.
Frequently Asked Questions
Will it fit my semi?
ATB designed it for saddle mounting on semi-trucks. Fit depends on your truck's dimensions and mounting points, so confirm your measurements before ordering.
What is a step saddle boot box?
It is a toolbox that saddle mounts on a semi-truck frame and doubles as a step, with Pro-Grip strut steps for footing and lockable storage inside.
Which mounting kit should I choose?
ATB lists four kits, none included: M2100C heavy duty (up to 500 lb), M3000C direct bolt-onto-frame (up to 300 lb), M3000H hook system (up to 300 lb) and M3050C bolt-on (up to 300 lb). Contact us if you want help choosing.
How do I measure for it?
Every A-SB51S is 25" tall and 28" deep. Measure the open frame length where it will mount to choose a width from 12" to 48", and check the mounting points on your truck.
Is it weather resistant?
ATB built it for weather resistance and tool protection: the top-hinged lid helps shed water, and the box is seam welded with gusseted corners.
What lock does it use?
A stainless steel dolphin tail T-handle lock, factory installed by ATB.
Installation
Stuck on a step?
- A-SB51S step saddle boot box
- Dolphin tail T-handle lock (factory installed)
Specifications
| Brand | ATB |
|---|---|
| Series | A-SB51S |
| Type | Step saddle boot box |
| Material | Aluminum |
| Finish | Smooth bright aluminum |
| Lid | Single top hinged lid |
| Steps | Pro-Grip strut steps |
| Lock | Stainless steel dolphin tail T-handle lock, factory installed |
| Construction | Seam welded, gusseted reinforced corners |
| Mounting | Kit sold separately: M2100C, M3000C, M3000H or M3050C |
| Made in | USA |
| Part number | A-SB51S-252812T-S |
| Part # | Size |
|---|---|
| A-SB51S-252812T-S | 25"H x 28"D x 12"W |
| A-SB51S-252814T-S | 25"H x 28"D x 14"W |
| A-SB51S-252816T-S | 25"H x 28"D x 16"W |
| A-SB51S-252818T-S | 25"H x 28"D x 18"W |
| A-SB51S-252820T-S | 25"H x 28"D x 20"W |
| A-SB51S-252822T-S | 25"H x 28"D x 22"W |
| A-SB51S-252824T-S | 25"H x 28"D x 24"W |
| A-SB51S-252830T-S | 25"H x 28"D x 30"W |
| A-SB51S-252836T-S | 25"H x 28"D x 36"W |
| A-SB51S-252848T-S | 25"H x 28"D x 48"W |
Warranty, shipping & returns
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Warranty
ATB covers its standard truck boxes with a 60-month (5-year) limited warranty for the original purchaser; it is not transferable.- For a warranty claim, contact us with your order number and photos and we will work it through with ATB.
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Shipping
Ships by freight from the ATB factory in Blanchard, ND; lift-gate delivery available.- Alaska, Hawaii and Canada: contact us for a freight quote before you order.
- We email your tracking details as soon as it ships.
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Inspect on delivery
Check the box when the freight arrives, before the driver leaves: look over the lids, doors, corners and welds for dents, scratches or shipping damage. Note any damage on the delivery receipt and send us photos. Check it as soon as it arrives.- Look for crushed ends, punctures or tears in the carton.
- If something looks wrong, take photos of the box and the parts (and if a driver asks you to sign, note the damage on the receipt).
- Open the box and check the parts against the parts list before you install.
- Email support@prestigetruck.com right away with your order number, a short note and photos. We send a replacement or a full refund at no cost to you.
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30-day returns
Return it within 30 days of delivery, unused, in the original packaging, with proof of purchase.- Email support@prestigetruck.com with your order number. We reply within 1-2 business days with instructions.
- Damaged, defective or wrong item: we send a prepaid label or arrange a pickup.
- Changed your mind: you pay return shipping. No restocking fee.
- Refunds go back to your original payment method within 7 business days of approval. See our returns policy.









