Sono-Tek (OTCMKTS:SOTK – Get Rating) was downgraded by Zacks Investment Research from a “hold” rating to a “sell” rating in a research note issued to investors on Tuesday, Zacks.com reports. According to Zacks, “Sono-Tek Corporation is a developer and manufacturer of ultrasonic coating systems for applying precise, thin film coatings for the microelectronics/electronics, alternative energy, […]