Before revision: , The undine is a spherical or pear-shaped glass flask generally about 2 – 3 inches in diameter with a 2-3 inch narrowing spout on one side and a collared opening on the top of about half an inch width .
After revision: , The undine is a spherical or pear-shaped glass flask generally about 2 to 3 inches in diameter with a 2 to 3-inch narrowing spout on one side and a collared opening on the top of about half an inch wide .