Fowler/Sylvac Mark IV and Mark V Indicators June 14, 2013 All good things must come to an end. The Fowler/Sylvac Mark IV and Mark V indicators have officially been discontinued. These two electronic indicators are used in thousands of machine shops and manufacturing facilities across the country. The Mark IV and Mark V indicators were some of the first electronic indicators to offer RS-232 (data collection) as a feature. Sylvac, who was the manufacturer of the Mark IV and Mark V electronic indicators, is working with Fowler to offer the generation of the Mark VI Electronic Indicators. The Mark VI electronic indicator has a few extra bells and whistles that the Mark IV and Mark V generations had including being IP67 protected and coming standard with a 5-year warranty. If you have any questions about the Fowler/Sylvac Mark VI Electronic Indicators, please email firstname.lastname@example.org.