The Stubby Bottle! Medicine Bottle Slide
Duane used a Coricidian bottle, but I play cigar box guitar. I've found something smaller and more powerful: a classic Morphine-style short bottle. It fits perfectly on the finger and covers three strings beautifully.
Height: 2 Inches 51 mm
Diameter: 1 1/4 Inches 31 mm
Opening: 3/4 Inch 19 mm