The 500 Series Send N' Blend Mix / Blend Module from Serpent Audio allows you to add a mix/blend function to any piece of outboard gear, allowing for enhanced parallel processing. It can be used for combining of two individual signals (dual mic'ing or typical summing applications).
 
The module features Elna capacitors, a sealed potentiometer, steel housing construction, and three-way hard bypass.
three-way
 
The Features 
Three-way hard bypass (Wet/Dry/Blend) (Relay Controlled)
Radial omniport rear panel connectivity
Steel housing construction
Sealed potentiometer
Protection from 48V Phantom power
VPR compliant
Made in the USA