Smart Research Guitar D.I. Deluxe System with power supply! Here is the manufacturer's description:

Designed to solve many instrument recording and D.i problems. For instance, one guitar feeding down long cables to 3 amps in a different area, without hums or change of tone. Includes: Balanced line driver for long cables; speaker level D.i input, and one unity gain Di Box/Splitter for two D.i or Amp feeds. Conceived at Real World Studios, to solve the problem of a guitarist wanting to play in the control room and have amplifiers set up in a live room sometimes several hundred feet away. Prototypes were also used at Virgin/ EMI Townhouse and Manor studios. Since then producers and artists such as Tom Lord Alge, Peter Gabriel, Paul Weller, and Tears for Fears have bought systems. Four systems were used to cure problems for Peter Gabriel's live show, where two stages had to be inter -connected with 300 feet of cable carrying guitar signals from radios to effects pedals on both stages and back to amps on the main stage without degradation, (allowing each stage to be patched independently).

The system comprises a TRANSMIT box and RECEIVE box. The TRANSMIT box has a high impedance input and line driver, which will drive long cables to the RECEIVE box input, which feeds the Di/splitter giving two isolated outputs.(In the Deluxe version, there are two Di/splitters in both the TRANSMIT and RECEIVE boxes, giving 8 isolated outputs) In addition, the RECEIVE unit has a speaker simulator input, so you can plug the speaker output of an amp in for 'dirty' Di sounds with or without a speaker connected. All the Di/splitters on both boxes have break jack inputs and can be used as separate Di's if desired, as well as earth lift switches to stop hum problems. This means there are a total of 8 outputs with the Deluxe version, (or 2 on the normal system); a line driver and receiver; and a speaker simulator.