Mighty Mule MM571W
#1 in Single swingFull review
A heavy duty single gate kit for long or heavy farm and estate gates that wants a UL 325 listing. Check the length and weight chart for gates over 8 ft.
Amazon $443.04$443.04
The Mighty Mule MM571W is the better automatic gate opener overall, rated 3.6 to 3.2. The Mighty Mule MM571W leads on warranty. The TOPENS A8131 wins on price. The TOPENS A8131 costs $84.04 less ($359 vs $443.04).
TOPENS A8131
#4 in Single swingFull review
A low cost opener for a heavy single gate near an outlet. Pick a UL 325 listed kit instead where the gate faces a public road or children.
Amazon $359$359
Prices were last checked November 2, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Mighty Mule MM571W for warranty (1.5-year warranty vs 1-year warranty).
- Choose the TOPENS A8131 for price ($359 vs $443.04).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every single swing automatic gate opener; a clear win is highlighted. How we rank explains each one.
| Factor weight | Mighty Mule MM571W | TOPENS A8131 |
|---|---|---|
| Overall rating | 3.6/5 | 3.2/5 |
| Gate weight 20% | 87 gates up to 850 lb per leaf | 89 gates up to 880 lb per leaf |
| Gate length 15% | 80 gates up to 18 ft per leaf | 80 gates up to 18 ft per leaf |
| Safety listing 15% | 100 UL 325 listed | 0 no UL 325 listing published, scored as none |
| Price 25% | 55 $443.04 | 72 $359 |
| Warranty 25% | 12 1.5-year warranty | 0 1-year warranty |
Specifications
| Mighty Mule MM571W | TOPENS A8131 | |
|---|---|---|
| Gate | ||
| Gate type | Single swing | Single swing |
| Heaviest gate | 850 lb | 880 lb |
| Longest gate | 18 ft | 18 ft |
| Time to open | 14 s | 15 s |
| UL 325 listed | Yes | - |
| Power | ||
| Power | Battery, solar ready | Battery, solar ready |
| Battery | 7 Ah | - |
| Motor voltage | 12 V | 24 V |
| Build | ||
| Remotes included | 1 | 2 |
| Weight | 30 lb | 24.5 lb |
| Warranty | 1.5 years | 1 year |