how many feet come in a 3 pk?

Both INDIVIDUAL packs - the 3/8" and the 1/2"- are 20 feet long.

no 1/4" one? either 20 or 50ft?

Not in this brand, but Amazon offers 1/4-inch backer rod in various lengths, from 10 feet to 100 feet, from other brands. Just search on "Backer Rod 1/4 Inch".

can the backer rod be sliced for smaller openings?

I have not done that, but it cuts easily with a sharp knife or scissors, so you should be able to slice it to fit whatever opening you have. It's good stuff!

Can his be used for exterior windows before caulking?

I used it to push into larger cracks in my driveway before applying concrete filler, and it worked great. I'm thinking that it should work well for filling in spaces around your windows prior to caulking.

Fully operational. Shipping worldwide, on schedule.Customs & duties included in the price

Help Track order

Account Cart

Fully operational. Shipping worldwide, on schedule.Customs & duties included in the price

Help Track order

Account Cart

M-D Building Products - Versatile Gray Foam Backer Rod - Essential Caulk Saver for Sealing Concrete Gaps, Expansion Joints, and Crack Filling, 3/8 by 20 Feet (71464)

M-D Building Products - Versatile Gray Foam Backer Rod - Essential Caulk Saver for Sealing Concrete Gaps, Expansion Joints, and Crack Filling, 3/8 by 20 Feet (71464)

Product ID: 270390717

Details

Brand
M-D Building
Colour
Gray
Item form
Foam
Item weight
0.6 Ounces
Maximum gap fill
0.38 Inches

💧Waterproof foam material

📏3/8-inch gap fill precision

🛠️20 feet versatile length

B/.74

Duties & taxes included

In stock

Sold byAmazon PanamaDelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

Buyer Protection · Full refund if your order doesn't arrive as described.

Desertcart purchases this item on your behalf and handles shipping, customs, and support to Panama.

Secure transaction

Description

🛠️ Seal Smart, Save Big – The Pro’s Secret to Flawless Finishes!

EXTENDED REACH - Generous 20-foot length ensures you have enough material for multiple projects or large surfaces.
EASY CUSTOMIZATION - Easily trimmed with scissors and twistable for larger gaps, giving you total control over your seal.
PRECISION GAP FILLER - Perfectly sized 3/8-inch diameter to seal and insulate with professional accuracy.
DURABLE WATERPROOF FOAM - Crafted from resilient rubber foam that blocks drafts and moisture, enhancing longevity.
MULTIPURPOSE APPLICATION - Ideal for expansion joints, concrete cracks, driveways, and sidewalks—your go-to caulk saver.

The M-D Building Products Versatile Gray Foam Backer Rod is a 3/8-inch diameter, 20-foot long waterproof foam rod designed to fill and seal concrete gaps, expansion joints, and cracks. Manufactured in the USA, it provides a durable, flexible base for caulking, preventing drafts and moisture intrusion while being easy to trim and customize for various gap sizes.

Specifications

ASIN	B000BQS90G
Best Sellers Rank	#72,887 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #427 in Hardware Sealers
Brand	M-D Building Products
Brand Name	M-D Building Products
Color	Gray
Colour	Gray
Customer Reviews	4.6 out of 5 stars 1,586 Reviews
Global Trade Identification Number	00043374714647
Included Components	MD Building - 71464 - 2pk
Item Form	Foam
Item Type Name	MD Building - 71464 - 2pk
Item Weight	0.6 Ounces
Item form	Foam
Item weight	0.6 Ounces
Manufacturer	M-D Building Products
Material Type	Rubber
Maximum Gap Fill	0.38 Inches
Maximum gap fill	0.38 Inches
Model	71464
Number of Items	1
Part Number	71464
Surface Recommendation	wall
Surface recommendation	wall
UPC	043374714647
Unit Count	1 Count
Warranty Description	All M-D products are warranted to be free from defects in material and workmanship if installed and used in strict accordance with our installation instructions.
Water Resistance Level	Waterproof

Reviews

B**S

Great for posting my Dobermans ears thanks x

30.09.2023

U**T

Good low cost back rod

Used this foam to seal up the concrete around my 4inch pipe for Radon System before I caulked. I stuffed this around the pipe to fill in the gap and then covered it all with high quality caulk to seal it up perfectly. It worked perfectly and is far cheaper than what i found at my Home Center. Make sure to purchase a thickness that is a little wider than your gap so it make a tight fit.

8.04.2026

P**S

Very satisfactory

Good price for the quality of the product. Did the job.

13.06.2018

M**Y

Use THESE, not spray foam

Sometimes caulking or spray foam is not appropriate for the job, and is an excellent permanent base fix prior to caulking. Creates no pressure on door and window frames

24.10.2025

A**W

Does what it was made for

Did exactly what it was designed to do.

12.10.2025

Common Questions

Are the products genuine and authentic?+

Yes, all products are sourced directly from authorized retailers in the US, UK, UAE and India. We maintain strict quality control processes and verify each product before shipping. All items come with applicable manufacturer warranties and are covered by our standard return policy.

How long does delivery take and is it reliable?+

Delivery times vary by destination country, typically ranging from 3-9 business days. Each order is fully trackable through our system. We handle all customs clearance and use reliable courier partners for last-mile delivery. You'll receive regular updates about your order status via email and our app.

What is Desertcart? Is it safe to order from?+

Desertcart is an international e-commerce platform operating since 2014. We securely process thousands of orders globally each day. Every product goes through our quality verification process before delivery, and we provide end-to-end order tracking, 24/7 customer support, and a comprehensive returns policy to ensure a safe shopping experience.

How is product pricing calculated?+

Our prices include the product cost, international shipping, import duties, customs clearance, and local delivery charges. We handle all customs and import procedures, ensuring there are no hidden fees upon delivery. PRO members receive additional benefits including free shipping.

Trustpilot

TrustScore 4.5 | 7,300+ reviews

Reema J.

Perfect platform for hard-to-find items. Delivery was prompt.

1 month ago

Fatima A.

Best international shipping I've ever tried. Worth every penny!

3 days ago

View all Trustpilot reviews

B/.74

Duties & taxes included

In stock

Sold byAmazon PanamaDelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

Buyer Protection · Full refund if your order doesn't arrive as described.

Desertcart purchases this item on your behalf and handles shipping, customs, and support to Panama.

Secure transaction

Trustpilot

TrustScore 4.5 | 7,300+ reviews

Imran F.

Very reliable shop with genuine products. Will definitely buy again!

2 weeks ago

Sneha T.

Received my product in pristine condition. Great service overall.

1 month ago

View all Trustpilot reviews