Roland GR-33B

In the July 1982 issue of Guitar World magazine, Sting was reported to be using a Roland Electronics bass synthesizer for special effects - referring to the Roland GR-33B bass guitar synth, which could be controlled with a G-88 or G-30 bass guitar. However, the validity of this information about Sting using one is doubtful owing to the lack of photographic evidence.

Source

 * Guitar World, July 1982 (pg. 37)