Zyglo7 ZE-4B is a biodegradable, reddish, slightly viscous liquid used for the emulsification of Zyglo7 PE penetrants. It is a general-purpose emulsifier with a moderate rate of action that can be used in open tanks due to its low volatility and high flash point. Ready to Use. Free flowing, white fluffy powder used as a high sensitivity dry powder developer for Zyglo Penetrants. Forms thin coating on parts to enhance the indications of defects. High purity composition allows it to be used in applications where high purity is essential to the testing process.