On July 21st evening, after Hong Kong protesters defaced the emblem of Beijing's Liaison Office in Hong Kong, HK Police shot at them from a bridge in Sheung Wan with sponge bullets made by Florida Company ALS Less Lethal, as identified by American Politics scholar, Dr. Anders Corr. "A sponge bullet featured in the video of police shooting in HK appears to be of the type manufactured by a Florida company." The product name is 4006D REACT, a 40mm direct fire round with a velocity of 325 fps (100 m/s) and a max effective range of 120 ft.
If the police had no rubber bullets, they might use live rounds
When asked if American citizens should request the US Government to ban the export of such bullets to HK and China, Corr said, "I thought about it, but there is a danger that if the police had no rubber bullets they might use live rounds. I think it is more effective to boycott China generally until they grant democracy to Hong Kong. We should put Magnitsky sanctions on those individuals in Hong Kong who are responsible for police and Triad violence against peaceful protesters."
Surplus of Weapons from Vietnam War Used against HKers
According to ALS's PRODUCT DESCRIPTION, "The 4006D REACT is a 40mm direct fire round designed as a blunt trauma pain compliance round. It is highly accurate and effective across a broad range of distances. It is recommended the operator attend an ALS less-lethal instructor training course to better understand product performance and injury potential."
Note: The footage of the round as we see it in the video could be from any video.