Features Fully differential all-tube circuitry, plus custom-wound Manley input & output transformers for that big MANLEY sound! All controls are built with 1% metal film resistors on sealed gold-contact Grayhill switches for maximum repeatability Independently regulated B+ and heater power supplies for maximum performance Dual Input, Attack, Recovery, Threshold, Output, LINK, and High-Pass side-chain filter for versatility Unit is hand-wired with silver solder and audiophile-grade componentry Description Product Description An industry standard for professional mastering studios, the Mastering Version of the Stereo Variable Mu Limiter/Compressor employs metal-film resistors loaded onto beautiful Grayhill sealed gold-contact switches for absolute repeatability, accuracy, and reliability. 1/2dB steps ensure precise and subtle adjustments. This is what defines mastering. High Pass Side Chain mod now comes standard.