Anhydrous calcium sulfate is a byproduct of hydrogen fluoride made from sulfuric acid and fluorite. The main component is CaSO4. Anhydrous calcium sulfate is also know as fluorgypsum.
Colorful round pen holder makes it easier to hold pens.The pen holder is one of the stationery. For the barrel of vessels holding pens, mostly straight mouth, straight wall, mouth base, relatively simple shape, no big changes.