Gary Cooper built the bass for Kool Bell in 1973. It was his first production instrument under his Oasis brand. I bought his first production guitar at the same time. It was a semihollow, with stereo low impedence Bartolinis. The Oasis company lasted 3 or 4 years, I think, though Gary continued to make special-order instruments under that name until his passing about 5 years ago. He worked as a guitar tech in the Sacramento area for 25 years after his Oasis venture and was a real treasure to musicians living in the central valley of California.