The STG Difference Free Domestic Shipping For Orders Over $99 Hassle Free Returns No Restocking Fees Price Match Guarantee Customer Rewards, Earn STG Cash

Koso Honda Grom Mini 3 Air/Fuel Ratio Gauge

Click to see 4 more pictures
$115.95 $104.36
(You save $11.59)

Customer Service

  • 888.784.4327
  • Monday-Friday
  • 10am to 6pm EST
  • Saturday
  • Closed
  • Free Domestic Shipping for Orders over $99Any domestic order (lower 48 United States) over $99.00 ships for free! If your item isn't over $99 but your total cart value is, you'll qualify for free shipping as well! For more information on our Shipping Policies, click here.
  • Hassle Free Returns No Restocking FeesHere at STG we want any return or exchange to be quick and pain-free. You can contact anyone here to expedite your return or exchange and we'll make sure it's handled ASAP. For more information on our policies, click here.
  • Price Match GuaranteeFind a better price? If you have we will match it! Call us at 888.784.4327 or submit a request here and our team will make it happen. *Some exclusions may apply.

Frequently Bought Together

Please choose Options for all selected Products

  • Choose Options

Our Mini 3 – Air/Fuel ratio gauge is designed to assist you to tune properly your engine and help you avoid engine problems. Just connect the meter to the 12v.DC power source and plug it to your OEM oxygen sensor and you're ready to go!


  • Plugs into the OEM oxygen sensor
  • A/F ratio display range: 12.2:1~17.2:1 display unit: 0.1
  • 12 Volts DC
  • Dimensions: 60 mm x 30 mm x 11.5 mm
  • Top clamp or Mini 3 universal gauge mount sold separately

Koso Installation Instructions Instructions & Exploded View