Installed digital volt/amp gauge in PA 28-181. Great unit easy to install. Much better than original.
S-300 External Shunt
FAA Approved Accessory
- PMA’d
- 300 Amp
- 3.25″ (W) x 1.75″ (D) x 1.75″ (H)
- 11.5 Oz Unit
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Product Overview
Prices
Retail Prices
Package includes:
- S-300 Shunt
- Installation Instructions
Description
Package
Retail Price
S-300 External 300 Amp Shunt
S-300
$60

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Testimonials
Customer Testimonials
EI representatives… have been very helpful, truthful, and knowledgeable… We had no idea, that a few weeks later [after our purchase], we would need to have a Top Overhaul. What great timing! Having your engine monitor installed in our plane will hopefully help us keep it out of the shop for further engine repairs.
- Customer
Phillip B. From Oklahoma
- Aircraft
Cessna 210N Centurion / Turbo Centurion
- EI Instrument
Just about to begin flying with the EI MVP-50P, so no in-flight feedback yet. But I did study the user manual, then sat in my plane going through the screens, menus, etc. It was very easy and intuitive to locate everything, so I’m confident that it will become second nature to do this in flight… Very happy with all interactions with EI.
- Customer
Robert B. from California
- Aircraft
2002 Diamond DA40-180
- EI Instrument
I have worked with your products before and I like them.
- Customer
David K. from New Mexico
- Aircraft
Cessna T20N Turbo Centurion II
- EI Instrument
The OPT-1 is more readable than the factory Cessna oil pressure/temp gauges.
- Customer
Daniel N. From California
- Aircraft
Cessna 175 Skylark
- EI Instrument
Works Great! Love it!
[Customer service] is great!
- Customer
Paul Z. from Oregon
- Aircraft
Cessna 182A Skylane
- EI Instrument
I have heard only great words about EI… Won’t be able to install till at least April but I know you are very helpful when it comes to questions.
- Customer
Thomas W. from Virginia
- Aircraft
Piper PA-30 Twin Comanche
- EI Instrument
Very affordable… great installation instructions. [I chose EI because of its] price point, certified primary.
- Customer
Benjamin T. from South Carolina
- Aircraft
Piper PA-28-181 Archer II
- EI Instrument
Excellent customer service. Without a doubt the best aviation part I have purchased.
- Customer
Alan B. from Florida
- Aircraft
Reid and Sigrist R.S.1 Snargasher
- EI Instrument
Very easy to install and directions were straight-forward.
- Customer
Paul H. from Oklahoma
- Aircraft
Piper PA-28-151 Cherokee Warrior
- EI Instrument
Great product. [I chose EI because] you have no competition.