My4Sons M4 Agitator
The M4 with a built-in agitator, for anyone spraying powders or mixes that settle in the tank.
Amazon $299.99$299.99
The My4Sons M4 Agitator is the better battery backpack sprayer overall, rated 3.7 to 3.2. The My4Sons M4 Agitator leads on features, runtime or airflow and value. The Milwaukee M18 Switch Tank wins on spray power. The My4Sons M4 Agitator costs $99.01 less ($299.99 vs $399).
Prices were last checked November 9, 2026. Product prices and availability are accurate as of that date and are subject to change; the price and availability shown on Amazon or the retailer's site at the time of purchase apply. As an Amazon Associate we earn from qualifying purchases.
Milwaukee M18 Switch Tank
A powerful 4-gallon sprayer for Milwaukee M18 owners, especially pros spraying harsh chemicals.
Amazon $399$399
Which should you buy?
- Choose the My4Sons M4 Agitator for features (battery and charger included, adjustable pressure, 4 or more nozzles, metal wand, agitator vs adjustable pressure), runtime or airflow (50 tanks per charge (200 gal) vs 20 tanks per charge (80 gal) with a battery sold separately) and value ($75 per gallon of tank ($299.99, 4 gal) vs $99.75 per gallon of tank ($399, 4 gal)).
- Choose the Milwaukee M18 Switch Tank for spray power (up to 140 PSI vs up to 80 PSI).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every 4 gallons and up battery backpack sprayer; a clear win is highlighted. How we rank explains each one.
| Factor weight | My4Sons M4 Agitator | Milwaukee M18 Switch Tank |
|---|---|---|
| Overall rating | 3.7/5 | 3.2/5 |
| Value 25% | 30 $75 per gallon of tank ($299.99, 4 gal) | 12 $99.75 per gallon of tank ($399, 4 gal) |
| Tank size 10% | 67 4 gal tank | 67 4 gal tank |
| Spray power 20% | 71 up to 80 PSI | 100 up to 140 PSI |
| Runtime or airflow 20% | 100 50 tanks per charge (200 gal) | 60 20 tanks per charge (80 gal) with a battery sold separately |
| Features 15% | 90 battery and charger included, adjustable pressure, 4 or more nozzles, metal wand, agitator | 20 adjustable pressure |
| Warranty 10% | 0 warranty not published, scored as none | 50 3-year warranty |
Specifications
| My4Sons M4 Agitator | Milwaukee M18 Switch Tank | |
|---|---|---|
| Spraying | ||
| Tank | 4 gal | 4 gal |
| Max pressure | 80 PSI | 140 PSI |
| Max flow | - | 0.5 GPM |
| Nozzles included | 9 | - |
| Wand length | 48 in | - |
| Hose length | 60 in | - |
| Power | ||
| Battery | 12 V 8 Ah, included | 18 V, sold separately |
| Runtime per charge | 6 hours | - |
| Gallons per charge | 200 gal | 80 gal |
| Tanks per charge | 50 | 20 |
| Features | ||
| Adjustable pressure | Yes | Yes |
| Metal wand | Yes | - |
| Agitator | Yes | No |
| Gauge or control panel | No | No |
| Build | ||
| Warranty | - | 3 years |