Specially designed single-phase perturbation attenuation isolating transformers with high transient suppression and low noise level. Designed and tested according to norm EN61558-2-19. ISO transformers are electro-statically shielded and have output filters which protect systems from unwanted "noise" and high frequency voltages that can occur due to switching and loading on distribution lines. Portable type, easy installation. Designed to protect equipment that requires a low-noise voltage in order to work without problems e.g.: computer equipment, telephone exchanges and audio-equipment.