bing tracking image
  1. Accessories and Parts
  2. Redline
  3. RV Vents and Fans
  4. Roof Vent
  5. Replacement Vent
Replacement Exterior Half-Moon Trailer Vent for 3" Diameter Hole - Black

Replacement Exterior Half-Moon Trailer Vent for 3" Diameter Hole - Black

Item # HMAV2
Our Price: $10.83
Accessories and Parts
Orders above $50 qualify for Free Shipping
Shipping Weight: 0.25 lbs
In Stock
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

Need help with installation?
Locate installers near me
This half-moon-shape vent forms the exterior part of the Alliance 2-piece enclosed trailer vent. Constructed of UV-resistant polypropylene plastic that holds up to sun exposure. Black color. 1-833-496-1390 to order Redline accessories and parts part number HMAV2 or order online at Free expert support on all Redline products. Guaranteed Lowest Price and Fastest Shipping for Replacement Exterior Half-Moon Trailer Vent for 3" Diameter Hole - Black. Accessories and Parts reviews from real customers.
  • All Info
  • Reviews (21)
  • Q & A (0)
  • Videos (2)
  • Photos
  • Why etrailer?

Redline Accessories and Parts - HMAV2

  • RV Vents and Fans
  • Roof Vent
  • Replacement Vent
  • Redline

This half-moon-shape vent forms the exterior part of the Alliance 2-piece enclosed trailer vent. Constructed of UV-resistant polypropylene plastic that holds up to sun exposure. Black color.


  • Exterior vent is the outside part of the Alliance 2-Piece Polypropylene Trailer Vent for 3" Diameter Hole
    • Fits round interior trailer vent (AVT2; sold separately)
  • Half-moon piece with flat, slotted side attaches to trailer's exterior
    • Slots are on one side only, allowing you to position the vent for best airflow and to help prevent water from getting in
    • Drain holes at the corners let out any water that does get in
  • UV-resistant, polypropylene plastic construction stands up to the elements
  • Black color
  • Overall dimensions: 8" long x 6" wide x 1-1/4" tall
  • Flange width: 1/2"
  • 6 Screws (sold separately) required for installation
    • Hole diameter: 3/16" (fits #8 screw)
  • Sealant sold separately

HMAV2 Alliance Outside Half of 2-Piece Enclosed Trailer Vent - UV Resistant Polypropylene Plastic - Black

Video of Replacement Exterior Half-Moon Trailer Vent for 3" Diameter Hole - Black

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Redline 2-Piece Polypropylene Trailer Vent Review and Installation

Jake: Hey guys, it's Jake here with etrailer. Today we're going to be taking a look at the Redline half-moon trailer vent. This is going to allow fresh air to get in and hot air to get out without having to worry about getting any water inside your trailer.In this kit, you are going to get the outside vent and the inside receiver so that you can have a nice clean look on the inside of your trailer. This is really going to be important for if you have a wall inside your trailer like we do, but if you don't have a wall, you can just use this part and you'll be able to mount it to the outside of your trailer and get fresh air without having to worry about any water.So you can buy these as a kit or you can buy them separately. Now here you'll see we have our vent in black. It's also available in white if you'd like to match it to your white trailer.Here's that piece on the inside wall that we we're talking about.

This is going to give it a nice clean look so you just don't have an open hole in your wall. It's going to have a nice flush mount design so you don't have to worry about anything running into it when it's on the wall. It's also going to help preserve this part from being damaged.If you want more of a cross-flow to go into your trailer, you could pick up a couple of these vents to be able to put one on the opposite corner of your trailer so that you have wind coming in the front and going out the back. When using two vents, it's going to provide a way for cool air to get in and warm air to get out. Now that we've gone over some of those features, let's go ahead and show you how we got it installed.We'll start by drilling a 3" hole.

We're going to start on the inside so that we know we're not going to run into anything inside the walls. You can see we have our ribs here and here, so we're going to split the difference and do it in the middle of them. Then we're going to continue with the hole saw through the sheet metal on the outside so we know where our hole needs to be drilled. We'll go ahead and insert our pilot bit into the hole that we punctured through the sheet metal and start drilling out our hole.I'm going to go ahead and insert our vent on the inside and fasten it down. Here we just found some stainless steel screws so we don't have to worry about any rust.

Now we can move to the outside, and we can go ahead and get our outside vent in place, slide it over. We'll use a self-tapping screw, but you want to be careful with this sheet metal on the outside of your trailer. It's not very thick. You don't want to strip it out. We'll stop right there and hand-tighten from here.

Now we'll go ahead and get the other five screws in place.Now, we went ahead and put some of this Loctite black silicon gasket on the inside. We took our cover off and put it on the inside to seal it up nice and neat to make it a nice watertight seal. We do have this at etrailer. You can pick some up if you'd like.Once you have all your screws in place, you're ready to hit the road.With all that being said, that's going to do it for our look and installation of the Redline half-moon trailer vent.

Customer Satisfaction Score:

Customer Reviews

Replacement Exterior Half-Moon Trailer Vent for 3" Diameter Hole - Black - HMAV2

Average Customer Rating:  4.9 out of 5 stars   (21 Customer Reviews)

This half-moon-shape vent forms the exterior part of the Alliance 2-piece enclosed trailer vent. Constructed of UV-resistant polypropylene plastic that holds up to sun exposure. Black color.


Awesome delivery.


I ordered this vent online to replace an existing vent which had been damaged. The vent arrive in about a week. There was conformation email and tracking history through transit. The vent fit perfectly utilizing the existing mounting holes with no additional drilling. Excellent product and I would purchase rom this company again


Vent is made of very tough plastic material. Should provide many years of service in our outdoor electric panel box.


Quality stuff!


Bought replacement vent cover. It fit perfect. Received it very quickly.


Exactly what I needed!

as fast, and entire transaction was super easy.

Thanks Etrailer!


just recv'd product and shipment was fast/ item seems to be sturdy waiting on weather to cool a bit before I do install....

Working just fine and trailer fills a bit cooler...thx
Edward W - 06/02/2020


It's great when one does business with a EXCELLENT rating . items just what I wanted and the shipping gets done right away.

try them you will be pleased. !


Perfect fit just what I needed thanks


It’s a plastic cover ….


this is the other half and it to was easy to install


Product was as promised and delivered in a timely manner. Great service.


Did what I needed it for


Product was received as advertised and fit was perfect!


Order arrived way ahead schedule.


what i expected



exactly as described on-line






See what our Experts say about this Redline Accessories and Parts

< Previous

Do you have a question about this Accessories and Part?

  • Why

    At we guarantee:
  • Real product know-how.

    We make sure that the products we sell are what we say they are, and that they work the way they are supposed to work. Get real advice from a real person who has the knowledge and expertise needed to solve your problem.
  • Most detailed, accurate accessories and part information available.

    Because we take providing accurate product information seriously, we take our own detailed product photos, demo videos and installation videos, as well as verify measurements, instructions, and vehicle fit information.
  • Installations, made easy.

    We love helping people and have the most highly-trained customer service, hands-on experience, step by step videos and installation instructions.
  • Fast shipping.

    Your order is automatically routed to get out of our warehouse and to your door as quickly as possible. Receive free shipping on orders over $99.
  • Personalized service for life.

    We provide one-on-one, personalized service from the ordering process through the life of your product.
  • Trusted since 1946.

    We've been serving customers since our parts store first opened in 1946 and continue to be recognized by our customers, our vendors and third parties for exceptional service.
  • Returns Policy

    Need to return an item? No problem. Please read our Returns Policy for more information.

Info for this part was:

Employee Raymond P
Written by:
Raymond P
Employee Jameson C
Expert Research:
Jameson C
Employee Cole B
Installed by:
Cole B
Employee Jacob H
Installed by:
Jacob H
Employee Chris R
Video Edited:
Chris R

At we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.

Product Experts Available Now!
Call 1-833-496-1390