MAC Instruments Share: IndustriesManufacture MAC Instruments Visit Website 3410 Tiffin Ave. Sandusky, OH 44870 (419) 621-2322 (419) 621-2321 (fax) macinstruments.com/ About Map About We have been manufacturing high quality, heavy duty, industrial instruments in Sandusky, Ohio USA since 1990. We are the world leader in high temperature moisture measurement in industrial processes. What's Nearby? Distance: 5 10 15 20 25 50 mi.