Hydro strut gauge

This gauge is used for adjusting the strut of a hydro.  Slide gauge under the hull and set to the desired height.   Saves hassle trying to fumble around with rulers, tighten the nuts all at the same time.  
Easy place the gauge to height needed for adjustment, hold hull to table to gauge and tighten the nuts.   
The gauge runs 18mm to 24mm in steps.