Helix M FOUR 4-Channel Amplifier with Integrated Active Crossover


Expanded Audio Features Combined with Ridiculous Power and Intelligence from Helix

If you're a fanatic for amazing sound, the Helix M FOUR is precisely the right way to go. This amplifier will fire up your speakers in no time with an abundant 135 Max Watts RMS per channel on a scaled-down footprint. Perfect for integration with factory Harley radios, the M FOUR has many features distinguishing it from any other amps ever conceived.

Tap Into Your Factory Radio For a Clean, Well-Defined Sound

The M FOUR is equipped with many intelligent attributes to help it quickly adjust to all installation challenges of modern factory Harley radios. The extensive audio features will offer a sound quality at its best.

This Amplifier is Totally Cool

The M FOUR stays cool thanks to the highly efficient Class D design topology, allowing you to listen for many hours without overheating while it delivers up to 540 Watts of clean and undistorted output power.


  • Integrated, Adjustable Crossover: highpass, lowpass, and bandpass
  • Input Mode Switch makes for flexible input signal routing
  • Automatic Turn-On Function
  • Compact footprint
  • High output power of 135 Watts RMS
  • Intelligent high-level input makes for easy integration into factory Harley radios
  • Surface Mounted Device manufacturing technology combines minimum space with maximum reliability
  • Exclusive clean and efficient design


  • Output Power RMS: 4 x 100W @4 Ohms; 4 x 100W @2 Ohms; 2 x 200W Bridged @4 Ohms
  • Max Output Power/Channel: 135W RMS @2 Ohms
  • Amplifier Technology: Class D
  • Inputs: 4x RCA; 4x High-Level Speaker Input; 1x Remote In
  • Input Sensitivity: RCA 0.5-6V; High Level 1.3-13V
  • Input Impedance: RCA 20 kOhms; High Level 13 Ohms
  • Outputs: 4x Speaker Output
  • Frequency Response: 10 Hz-30,000 Hz
  • Highpass: 15 Hz-4,000 Hz adj; Lowpass: 40 Hz-4,000 Hz adj; Bandpass: 15 Hz-4,000 Hz adj
  • Slope High/Lowpass: 12 dB/Oct
  • Signal-to-Noise Ratio: 98 dB
  • Distortion (THD): 0.05 %
  • Damping Factor: 100
  • Operating Voltage: 10.5-16V (Max. 5 sec. down to 6V)
  • Fuse: 2 x 30A Maxi-fuse (APX)
  • Dimensions: 2.00" H x 9.06" W x 6.06” D


  • 2014 - Present Street Glide, Electra Glide, Ultra. The amp installs nicely in the fairing on top of the radio.
  • 2015 - Present Road Glide. Will require slight modification to headlight bracket and headlight plastic mounting tabs.
  • Note: This will not fit in the fairing of a 1998 - 2013 Road Glide or Street Glide.
  • For all installation questions: Please see our Helix M FOUR Amplifier Installation Guide

What's In The Box?:

  • (1) 4-Channel Amplifier with Integrated Active Crossover
  • (1) Pair Front Speaker Pod Connectors
  • (1) Remote Wire
  • (1) Pair Signal Input Wire 
  • (1) Mounting Pad with Adhesive
  • (1) Instruction Manual


Typically ships in 1 to 3 business days. We process and build orders in the order in which we receive them. This method allows our experts to review every order and check that it is correct for your specific bike, which means sometimes you might wait a little longer to receive your order, but it's always worth it!


  • Helix Components: 1 Year
Shipping This Item Ships to The United States 

Items built to order have a build time of up to two weeks before shipping. Items that are not built to order (e.g. amplifiers, speakers, .etc) typically ship in 2 - 3 business days. Many of our speaker kits feature machined special parts and customized wire harnesses that are built to order. We process and build orders in the order that we receive them. This allows our experts to go over every order and check that your particular order is correct for your particular bike. This means sometimes you have to wait a little longer to get your order but it's always worth it! 

Once You Order Does Ship

You will receive an automated email with tracking information as soon as our shipping department creates a shipping label for your package.  


There are many more speakers, amplifiers, and kits to choose from than what you see here.

[powr-form-builder id=1f43a15c_1475460501]

Please allow 10 business days for your order to arrive if it is an item that is built to order. Items that are not built to order (e.g. amplifiers, speakers, .etc) typically ship the next business day.We process and build orders in the order that we receive them. This allows our experts to go over every order and check that your particular order is correct for your particular bike. This means sometimes you have to wait a little longer to get your order but it's always worth it! 

Returns are easy, simply contact us for a returns number and send your item to our returns centre for fast processing. We'll get you a replacement or refund in a snap! You can find our refund policy here.

Here are 5 great reasons to buy from us:



Easy Returns

Returns are easy, simply contact us for a return Authorization number and send your item to our returns center for fast processing. We'll get you a replacement or refund in a snap! You can find our refund policy here.



Your part is guaranteed to fit. We test fit every part we sell on actual bikes in order to verify fitment on each model, generation, and in each possible location. You can be sure that if we have stated that a part fits your bike, that it will, or your money back. You will find model, year, and location fitment details on most product pages.

Secure Ordering


Ordering from American Hard Bag is 100% safe and secure so you can rest easy. Your personal details are never shared, sold or rented to anyone either.



We Thoroughly Test Every Part We Sell on a Real Bike. There are a lot of parts out there that we refuse to sell. If it’s not up to our high standards, it never makes it to this website. We have parts that fit various budgets and levels of insanity, but all parts we carry are exceptional performers.



Because We Are Fully Authorized Retailers for All Brands We Sell, Manufacturers Warranties Are 100% Valid. There are only a select few authorized online retailers for the brands that we sell. Most all online retailers (even the really big ones) are not authorized at all! And the manufacturer's warranty is void before you even get your items.

Easy as 1 - 2 - 3!

We have 3 great financing options for you. Snap Financing, Installment Payments, and Split Pay. Learn more below.

No Credit Financing

12-18 months

4 Payments

Financing with Bread

Shop Online
Select Pay Over Time with Bread at checkout

Choose your plan - Easy Installments or Split Pay with your card of choice

Get your item now and pay over time!
It's that easy!

  1. Simple transparent terms. No prepayment penalties. No deferred interest.
  2. Applying is easy. All we need is a few pieces of information and you get a decision in seconds.
  3. Sign up for automatic payments and have the flexibility to change your due date if needed.
  4. Always know how much you’ll pay. Easy equal installments. No surprises.
  1. U.S. residents over the age of 18 (or over 19 for Alabama or Nebraska residents) are eligible, provided your identity can be verified.

  2. Checking your rate does not affect your credit score as only a soft pull is completed to check your eligibility. If you choose to finance your purchase with Bread after your pre-approval, we will not perform a hard inquiry with any of the three major credit reporting agencies. Once you have taken out a loan, Bread may report repayment information about your account to the consumer reporting agencies, which may impact your credit score. We may also obtain your credit profile from smaller credit reporting agencies.

  3. You will not be able to adjust your loan terms after you have checked out.

  4. You can apply via the website of any participating online store. When you’re ready to buy, click on Bread’s® financing button to get your rate in seconds. If you pre-qualify, you will be presented with the financing terms offered and sample payment amounts. Add the item to the retailer’s shopping cart and choose Bread® or “Pay Over Time” as your preferred method of payment when you check out.

Financing with Snap!

Get Approved

Could get approved for a lease purchase agreement of up to $3,000

*minimum finance $450

Instant Access

Get instant ACCESS to your financing upon approval


Get shopping! Snap lease-to-own financing lets you get what you need, when you need it.

  • 100 days same as cash - $0 in fees if paid off within 100 days
  • No hidden fees
  • No interest
  • No application fee
  • No credit needed and no hard credit inquiry - Bad credit/No credit OK!
  • High credit limits
  • 80% approval rate - All you need is a job making $1200 or more, be 18+ years old, and have an active checking account.
  • Snap doesn't offer traditional loans. Instead, we offer a consumer lease that allows you to finance the merchandise over 12-18 months of convenient payments. We also offer a 100-Day payment option, the best terms around. Need new tires for your car? Or new furniture for your growing family? Don't let bad credit stand in your way. Snap is your partner for fast and easy lease-purchase financing.
  • No Credit Needed refers to Snap’s lease-purchase financing that considers more than just credit reports to determine approvals or denials. In fact, applications for Snap’s lease-purchase financing aren’t even reported to TransUnion, Equifax, or Experian. Our proprietary decisioning process allows us to look beyond bad credit, no credit, and bankruptcy to approve more applicants.

Got Questions? 

Call American Hard Bag and we can help to see if Snap Finance is right for you!
1(888) 311-0016