Check the listing for details. Tachometer and Hour Meter for 2 & 4 Stroke Outboard Motors. Color: Black, Condition: New. Listed at 12.99 USD. Tachometer and Hour Meter ***Batteries are not user replaceable. This is not a permanent solution, but a way to determine your RPM for boats that do not have a permanent tachometer. Users have reported up to 3 years batter life (not guaranteed)*** Inexpensive way to tell if you are reaching WOT RPM 12V splashproof Tiny tach Works on 2 and 4 stroke motors Approxately 5-1/2' wire Simple installation: Just wrap tach wire tightly around spark plug wire 3-4 times and tape it to the plug wire. See included instructions for settings and operation info NOTE: I have tested a couple of these on my Yamaha 40hp and this tach displayed the same RPM as my factory tachometer. Product image is a representation only, product may have slightly different design/branding.Also works on other small engines such as lawnmowers, generators, etc. Listing and template services provided by inkFrog