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  • Home
  • Product Search
  • Benefits
    • Benefits
    • Testimonials
  • Discount Bundles
    • All Bundles
    • M4
    • M6
    • M4 + Agitator
    • M4 18-20V (DeWalt, Milwaukee, etc.)
    • M4 upgrade kits
      • Agitator upgrade kit
      • Battery upgrade kit
      • Electrical upgrade kit
    • M2
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    • Valve Handle Trigger
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    • HYDRAULIC
      • WANDS (14ft telescoping, 4 boom, etc))
      • HOSE (15ft, Coiled, Standard, Elbow, etc)
      • NOZZLES (QR, Flexi, Fan, Cone, , Multinozzle, etc)
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      • QUICK RELEASE/WASHERS/O-RINGS/ADAPTERS
      • Washers/O-rings
      • Quick Release
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    • ELECTRIC
      • Pumps
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    • STRUCTURAL
      • Lid
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      • Straps/Buckles
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      • Tanks
  • Videos
    • Videos
    • New Customer
      • Quick start
      • Overview of parts shipped with the M4 Backpack Sprayer
      • Nozzle kit Overview
      • Assembly and final inspection
      • My4sons Quality Care
      • Top 10 reasons why the MY4SONS M4 is rated #1 on amazon
      • M4: Charging and rotary switch use
      • How to prime the M4 Backpack Sprayer using A garden Hose
    • New For 2026
      • New For 2026
      • Monster Cart
    • Part/Accessories
      • 14 ft telescoping wand video
      • 14ft telescoping wand adapting to other sprayers
      • M4 New super wide XXL water Tight Lid Seal
      • Wide Lid Preview
      • Spray Pistol
    • Electric
      • New Wireless Remote Control for the M4!
      • 2021 Electrical Upgrade Kit
      • Battery and Multimeter
    • Troubleshooting
      • Quick Fix#1 no power, no voltmeter lights
      • Quick Fix #2 no power but voltmeter lights on
      • 5 step diagnostic checklist
      • M4: Charging and rotary switch use
      • Is my battery good?
      • Solving a collapsing tank
    • Maintenance
      • The best way to wire the M4
      • Securing Shoulder Strap anchor screw
      • Changing the red valve handle piston
      • Getting rid of leaks
      • How to prime the M4 Backpack Sprayer
    • Part Replacement
      • Replacing the pump
      • Replacing a broken pump neck
      • Replacing the red and rotary switches
  • About Us and FAQ
    • A Message From Our Founder
    • Assembly and final inspection
    • Customer Testimonials
    • Contact us
    • FAQ
Log in
    MY4SONS
    • Home
    • Product Search
    • Benefits
      • Benefits
      • Testimonials
    • Discount Bundles
      • All Bundles
      • M4
      • M6
      • M4 + Agitator
      • M4 18-20V (DeWalt, Milwaukee, etc.)
      • M4 upgrade kits
        • Agitator upgrade kit
        • Battery upgrade kit
        • Electrical upgrade kit
      • M2
    • Parts & Accessories
      • New Products
      • Valve Handle Trigger
      • Batteries
      • Wands
      • Pumps
      • Nozzles
      • HYDRAULIC
        • WANDS (14ft telescoping, 4 boom, etc))
        • HOSE (15ft, Coiled, Standard, Elbow, etc)
        • NOZZLES (QR, Flexi, Fan, Cone, , Multinozzle, etc)
        • VALVES/PISTOLS
        • QUICK RELEASE/WASHERS/O-RINGS/ADAPTERS
        • Washers/O-rings
        • Quick Release
        • Adapters
      • ELECTRIC
        • Pumps
        • Switches
        • Batteries
      • STRUCTURAL
        • Lid
        • Filters
        • M4 Pockets and storage
        • Straps/Buckles
        • Base plate screws
        • Tanks
    • Videos
      • Videos
      • New Customer
        • Quick start
        • Overview of parts shipped with the M4 Backpack Sprayer
        • Nozzle kit Overview
        • Assembly and final inspection
        • My4sons Quality Care
        • Top 10 reasons why the MY4SONS M4 is rated #1 on amazon
        • M4: Charging and rotary switch use
        • How to prime the M4 Backpack Sprayer using A garden Hose
      • New For 2026
        • New For 2026
        • Monster Cart
      • Part/Accessories
        • 14 ft telescoping wand video
        • 14ft telescoping wand adapting to other sprayers
        • M4 New super wide XXL water Tight Lid Seal
        • Wide Lid Preview
        • Spray Pistol
      • Electric
        • New Wireless Remote Control for the M4!
        • 2021 Electrical Upgrade Kit
        • Battery and Multimeter
      • Troubleshooting
        • Quick Fix#1 no power, no voltmeter lights
        • Quick Fix #2 no power but voltmeter lights on
        • 5 step diagnostic checklist
        • M4: Charging and rotary switch use
        • Is my battery good?
        • Solving a collapsing tank
      • Maintenance
        • The best way to wire the M4
        • Securing Shoulder Strap anchor screw
        • Changing the red valve handle piston
        • Getting rid of leaks
        • How to prime the M4 Backpack Sprayer
      • Part Replacement
        • Replacing the pump
        • Replacing a broken pump neck
        • Replacing the red and rotary switches
    • About Us and FAQ
      • A Message From Our Founder
      • Assembly and final inspection
      • Customer Testimonials
      • Contact us
      • FAQ
    Log in Cart
    • ROTARY SILVER ON/OFF ADJUSTABLE POWER SWITCH

      ROTARY SILVER ON/OFF ADJUSTABLE POWER SWITCH

      ROTARY SILVER ON/OFF ADJUSTABLE POWER SWITCH

      Regular price $ 6.99 USD
      Regular price Sale price $ 6.99 USD
      Unit price /  per 
    • Red On/Off Switch For M4

      Red On/Off Switch For M4

      Red On/Off Switch For M4

      Regular price $ 2.99 USD
      Regular price Sale price $ 2.99 USD
      Unit price /  per 
    • Electrical Refurb Kit for M4

      Electrical Refurb Kit for M4

      Electrical Refurb Kit for M4

      Regular price $ 19.99 USD
      Regular price Sale price $ 19.99 USD
      Unit price /  per 
    • Replacement Mini Fuses for M4 Charge Panel 20x5mm (See Warning)

      Replacement Mini Fuses for M4 Charge Panel 20x5mm (See Warning)

      Replacement Mini Fuses for M4 Charge Panel 20x5mm (See Warning)

      Regular price $ 1.99 USD
      Regular price Sale price $ 1.99 USD
      Unit price /  per 
    • PUSH ON PUSH OFF ROUND SWITCH (19MM HOLE)

      PUSH ON PUSH OFF ROUND SWITCH (19MM HOLE)

      PUSH ON PUSH OFF ROUND SWITCH (19MM HOLE)

      Regular price $ 4.99 USD
      Regular price Sale price $ 4.99 USD
      Unit price /  per 
    • Wireless Remote Control Kit for M4 and M6

      Wireless Remote Control Kit for M4 and M6

      Wireless Remote Control Kit for M4 and M6

      Regular price $ 39.99 USD
      Regular price Sale price $ 39.99 USD
      Unit price /  per 

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    Quick links

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    • User Manual For The M4
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    • Troubleshooting/FAQ
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    Final assembly and quality tested in the USA

    2 Year Warranty — 30 day returns for unused items minus the cost of shipping. / Patents Pending. / Please note that the M4 system is not compatible with muriatic acid.

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