CDHE: The Cylinder head Temp gauge probe end is a ring that replaces a spark plug washer. I can't recall cylinder head temp averages but most air cooled 4 stroke motorcycle engines cylinder temp range is approx 300f(150c) to 400f(205c) - very useful instrument. Tried an oil pressure gauge but had too wide of a range as oil pressure in Breganzies are around 3 to 5 psi max and barely registered; however, the needle did move enough to indicate flow - Never did find an oil pressure gauge with say an 8 to 10 psi max sweep so I replaced it with an ammeter gauge to balance out my instrument cluster design (Do not include the starter circuit when using a manual ammeter gauge ;o)