Milwaukee M18 FUEL 21mm
#1 in CordlessFull review
A cordless 21 mm polisher for large vehicles, for anyone already on the Milwaukee M18 platform.
Amazon $254.99$254.99
The Milwaukee M18 FUEL 21mm is the better dual action car polisher overall, rated 3.6 to 3.1. The Milwaukee M18 FUEL 21mm leads on correction and warranty. The SPTA 18V Cordless 15mm Kit wins on features. The Milwaukee M18 FUEL 21mm costs $5 less ($254.99 vs $259.99).
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.
SPTA 18V Cordless 15mm Kit
#3 in CordlessFull review
A complete cordless 15 mm kit at a low price, for occasional use where there is no outlet nearby.
Amazon $259.99$259.99
Which should you buy?
- Choose the Milwaukee M18 FUEL 21mm for correction (21 mm orbit vs 15 mm orbit) and warranty (3-year warranty vs 6-month warranty).
- Choose the SPTA 18V Cordless 15mm Kit for features (brushless motor, cordless or a 20 ft+ cord, lock-on trigger vs cordless or a 20 ft+ cord).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every cordless dual action car polisher; a clear win is highlighted. How we rank explains each one.
| Factor weight | Milwaukee M18 FUEL 21mm | SPTA 18V Cordless 15mm Kit |
|---|---|---|
| Overall rating | 3.6/5 | 3.1/5 |
| Correction 30% | 100 21 mm orbit | 62 15 mm orbit |
| Value 25% | 48 $254.99 | 47 $259.99 |
| Warranty 15% | 50 3-year warranty | 0 6-month warranty |
| Power 10% | 50 18 V battery; cordless makers publish no motor rating (neutral score used) | 50 18 V battery; cordless makers publish no motor rating (neutral score used) |
| Weight 10% | 50 weight not published (neutral score used) | 50 weight not published (neutral score used) |
| Features 10% | 15 cordless or a 20 ft+ cord | 50 brushless motor, cordless or a 20 ft+ cord, lock-on trigger |
Specifications
| Milwaukee M18 FUEL 21mm | SPTA 18V Cordless 15mm Kit | |
|---|---|---|
| Polishing | ||
| Orbit diameter | 21 mm | 15 mm |
| Speed range | 2,400-4,500 OPM | 2,000-4,800 OPM |
| Backing plate | 6 in | - |
| Forced rotation | No | No |
| Power | ||
| Power source | Cordless | Cordless |
| Battery | 18 V | 18 V |
| Batteries included | - | Yes |
| Cord | Cordless | Cordless |
| Brushless motor | Not listed | Yes |
| Controls | ||
| Constant-speed electronics | Not listed | Not listed |
| Soft start | Not listed | Not listed |
| Lock-on trigger | Not listed | Yes |
| Build | ||
| Pads or polish included | No | Yes |
| Warranty | 3 years | 6 months |