Only for gasoline engines.
You can measure the number of revolutions just by bringing it closer to the spark plug cord.
You can measure in the 1.2m range by using the attached antenna lead wire.
It can measure 2-stroke 1 to 4 cylinders and 4-stroke 1 to 6 cylinders and 8 cylinders.
gasoline engine 
2-stroke 1-4 cylinder
4-stroke 1-6, 8-cylinder

Item description:
Brand: OPPAMA                                                    
Item Name: Pulse Engine Tachometer
Part Number: PET-1100R
Size:
Battery life: 20000 hours
Measurement accuracy: ± 10r / min
Measurement range (rpm): 100-19980
Resolution (rpm): 10
Detection distance (mm): 150
Width (mm): 62
Depth (mm): 13
Height (mm): 120
Power supply: Built-in battery (non-replaceable)
Measurement method: Pulse detection
Weight: 73g
Other Details: Set: Antenna lead wire, Hanging string

Combine Shipping:
Please request invoice when you purchase multiple items. 
Handling Time:
We ship out within 3-5 business days after receiving payment.
Tracking Information:
We provide tracking number once item as shipped.
Customs duty:
Import duties, taxes, and charges are not included in the item price or shipping cost.
These charges are the buyer's responsibility.

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Payment is expected within 7 business days.

About Us:
We are specialized store in Japanese Tool brand.
Please contact us if you have any question.
Ninja Tools - 忍者工具店