Home > Door Seals > Automatic Door Bottoms > Surface Mounted > Zero #351, Automatic Door Bottom, Surface Mounted Casing with Neoprene Seal, .75" Drop

Zero #351, Automatic Door Bottom, Surface Mounted Casing with Neoprene Seal, .75" Drop

Zero #351, Automatic Door Bottom, Surface Mounted Casing with Neoprene Seal, .75" Drop
Product Specs for #351

This Zero International #351, Regular Duty, Surface Mounted, Automatic Door Bottom will ensure a proper and tight seal to the gap at the bottom of your door. Will block, sound, light, drafts and more. Equipped with a long-lasting, high-quality, neoprene seal and mechanism that has been tested to 5 million opening and closings. Smoke and Fire-rated, this ADB is available in 2 finishes and is custom cut to size.  View more details in the description tab below. 

How to Order: Selecting Finish and Exact Size required will determine total price. Note, product is priced per range with 18.25"-36" being the lowest priced range. To determine size required, see How to Measure for an Automatic Door Bottom.

Stock sizes - 30", 32", and 36" long are available to ship within 1 business day. Click here for our Quick Ship TMH Surface Mounted Automatic Door Bottom.

Price: $67.00
Size Range
Exact Size
Save to wishlist
SKU Z351AA|36
Shipping See Shipping Tab Below

Dimensions: Casing measures 1.793" x .722" and is made of .085" thick aluminum.

Colors:  Available in Clear Anodized and Dark Bronze Anodized Aluminum.  

Seal: Casing is fitted with solid neoprene seal with a maximum drop of .75". It can be used directly above the floor, or with a Doorway Threshold.

Compliance Details: Rated for fire and smoke and is UL Listed (see Product Data for details.)

Handing: Compatible with both right and left handed doors.

Installation: Model is designed to be surface mounted. Installation instructions and screws provided. Screws are colored to coordinate with casing.

Additional Options - Light Spring Strength: Light Spring Strength requires less operating force to activate than Standard Strength. Light Spring is compatible with ADA Compliant Doors and can be easily used by those with limited mobility. Can also be applied to sliding doors. Casing dimensions are the same. Contact our office at 845-388-1300 to purchase. 

Sizing: To determine sizing, see How To Measure For An Automatic Door Bottom.

Please note, images are for illustrative purposes only. They are not actual photos. Therefore, actual colors may vary slightly and size many be enlarged to show detail. See product specs for exact measurements.

This product has a 1 year guarantee against defects in material and workmanship.
Click to view our Full Warranty Policy.

Click here to view our Zero #365 Heavy Duty Automatic Door Bottom.

How it Works

How it Works: Automatic Door Bottoms utilize a concealed flat spring mechanism and plunger. When the door is closed, a brass plunger is compressed to automatically lower the seal, starting from the hinge side first. This motion ensures a smooth usage even on an uneven surface and prevents drag. The seal is automatically raised upon opening. These automatic door bottoms have been successfully tested through 5 million cycles!

See also About Automatic Door Bottoms.

Product Specs
Compliance Details

compliance details z351

Installation Guide

Click here for a Printable Copy of How to Install an Automatic Door Bottom.

Automatic Door Bottoms are available with three mounting options: Surface Mounted, Semi-Mortised and Fully Mortised. A surface mounted application can be applied without removing the door from its hinges. For a semi-mortised, if the rabbet in the door is cut-out already, the door does not need to be removed. For a fully mortised application the door should be removed before starting. 


Once your door is ready for installation you need to determine the size required for your door bottom:

  • For a Surface Mounted Application: Measure the distance between the two stop moldings, or if a perimeter door gasket is applied, measure the distance between the two installed gaskets, then minus 1/8-1/4"” (.125”) from the total distance. That is the size needed for your door bottom.

  • For a Semi-Mortised and Fully Mortised Application: Measure your door from side to side; that is the measurement needed for your automatic door bottom.

For visual presentation see How to Measure for an Automatic Door Bottom.

How to Install an Automatic Door Bottom- Figure 1

Once you have determined the size needed, if necessary, trim your door bottom. Use a chop saw or table saw to create a perfectly straight cut.

Note, Only trim opposite the actuating plunger, brass nut. (Trimming from the brass nut side will ruin your ADB).


How to Install an Automatic Door Bottom- Figure 1You can trim from the edge up to one inch of the screw in the side wall of the ADB.



How to Install an Automatic Door Bottom- Figure 3Surface Mounted and Semi-Mortised models need to be applied to the push side of the door only (the side with the door stops). The actuating plunger needs to be applied to the hinge side of the door for all applications.

Place the automatic door bottom against the door

Once you have the automatic door bottom leveled and positioned correctly, with a pencil or marker mark where the attachment screws need to be drilled.


How to Install an Automatic Door Bottom- Figure 4

To make installation easier you can drill a pilot hole which will ensure you attach the door bottom to the correctly marked spot. With the screws provided, screw in the automatic door bottom.

In some models, a plate is provided for the hinge side of the frame. This will protect the door frame from getting worn down by the actuating plunger. If provided, attach to corresponding point on the frame.



How to Install an Automatic Door Bottom- Figure 5Now that the door bottom is attached, test the door bottom by opening and closing the door to ensure there is a full seal. If the seal does not come down far enough twist the brass nut out, if it seals too tight twist the brass nut in.

Once you have followed through with all the instructions your Automatic Door Bottom is good to go! Enjoy years of quality sound, draft and light infiltration control with your new door bottom.

For additional assistance and product information, feel free to contact us. Our trained and friendly staff will guide you with all your soundproofing needs.


Shipping / Returns
  • Ship Time:
    • This product is custom made to your specifications, please allow 2-3 weeks to ship
    • *Similar or equivalent products from other manufacturers may be available to ship sooner. For expedited processing please contact our customer service department.
    • EXCEPTIONS: Gold Anodized Aluminum and Black Anodized Aluminum Products require 2-6 week processing time.
    • Ships via major carriers, such as UPS or FedEx Ground, with tracking information provided.
  • Domestic Shipping Fees- (Hawaii and Alaska not Included):
    • FREE SHIPPING on orders over $200.00 (excludes oversized and freight orders).
    • There will be a flat $19.99 shipping and handling fee on orders under $200.00.
    • Oversized Items: Items 86" and above have an oversize surcharge of $70.00
    • Freight Orders: Items 95" and above require freight shipment and have a shipping charge of $150.00
    • Orders totals above $1,500.00 will ship free, regardless of size.
  • Alaska and Hawaii, Canada, and International Shipping:
  • Returns:
    • This product is custom made and is not returnable.
    • We are commited to your satisfaction, as a courtesy, we may, at our discretion accept returns with a minimum 30% restock fee.
    • Weatherstripping products will not be considered for returns.
    • Item must be in new, resaleable condition.
    • Please call or email us to receive an RMA number before returning. No returns will be processed without an RMA number.
    • Return shipping is customer's responsibility. A return address will be provided with RMA#.
    • If you are shipping via USPS (not recommended) do NOT require signature as we will not be able to pick up your package from local post office facility.
Related products
Product reviews are only available to verified buyers of this product. To leave a review, please refer to the product review email we sent you.
  • Easy To Use (2)
  • Good Design (2)
  • Quality Materials (1)
  • Safety Features (1)
best uses
  • Inside (1)
  • Small Jobs (1)

Reviewed by 2 customers

Displaying reviews 1-2

By jrb1021

from Pennsylvania

About Me Avid Do-It-Yourselfer

Verified buyer
Easy and perfect
  • Easy To Use
  • Good Design
  • Quality Materials
  • Safety Features
best uses
Comments about Zero #351, Automatic Door Bottom, Surface Mounted Casing with Neoprene Seal, .75" Drop:
Purchased a custom built door for a small fortune which did not come with weatherstripping (or anything else). There was a gap under that door that was a problem for cold air in winter, and leaves and insects in spring/summer. After researching, I decided on this product. Measured it, sent the order. It arrived promptly, works perfectly, and was easy to install. Very happy with both the product and the speed of delivery.
Bottom Line Yes, I would recommend this to a friend

By Oops fixer

from Seattle, wa

About Me Casual Do-It-Yourselfer

Verified buyer
As advertised. Would purchase it again.
  • Easy To Use
  • Good Design
best uses
  • Inside
  • Small Jobs
Comments about Zero #351, Automatic Door Bottom, Surface Mounted Casing with Neoprene Seal, .75" Drop:
Accurately measured, well psackaged, and on point shipping.
Bottom Line Yes, I would recommend this to a friend
Displaying reviews 1-2
Recently Viewed