Image 1 & 2: Manta Gauge
The Manta Gauge Master was designed by Vicmarc and dns Germany.  The advantages of the Manta are:
Reduction of the edge angles to easy-to-remember numbers.
Reduction to 5 edge angles of woodturning tools with a clear classification via symbols.
Two practical checking options for the edge angle: sighting and insertion.
The shape of the tip of the tool is just as important as the bevel angle.  The Manta shows the correct profile of the most popular widths of spindle gouges i.e. 6, 10, 13 and 20mm.
For skew chisels you are able to check the bevel angle as well as the skew angle: 55 degrees or 77 degrees depending on your preference.
 
Image 3 & 4: Eccentric Chuck Gauge #1 & Eccentric Chuck Gauge #3
 
These above gauges are sizing tools which assist you in turning diameters to the exact sizes shown on the gauge.
Eccentric Chuck Gauge #1 = 10, 18, 22, 32 and 40mm cut outs
Eccentric Chuck Gauge #3 = 22, 40 and 52mm cut outs
 
Image 5: Gauge Master Center Finder
 
The Vicmarc Gauge Master was specially designed for wood turners to save time and money.  This device incorporates angle checking and centre finding.  This product is manufactured in Australia from injection moulded aluminium for durability.  It also includes symbols as a guide for sharpening angles of various tools.  The gauge master is clearly marked and easy to read