This is the Scubapro LS-1 compass. This compass got it's name from the south Texas dive operator Lonnie Sutherland. This compass was developed most likely by him in the 60's. Scubapro knew a good thing when they saw it and started to produce it under their name. I was fortunate enough to obtain this gauge NIB from a great dive buddy in Wisconsin. It has never been in the water and of course works great.