It's liquid DFE(1,1,-difluoroethane) that's commonly sold in certain stores as computer duster. It is used when neither dry ice or liquid nitrogen is obtainable. It's usually used for science, to freeze things, or just for fun cooling thermometers, water, or some insects. The computer duster can is used for dusting off the dust from computers using the DFE gas. however, when turned upside-down, it provides a frostbite causing super-cold liquid that's -25 degrees Celsius(-12 degrees Fahrenheit) or colder. It is sometimes(very very rarely) used to try to liquefy formaldehyde or other gases, but due to the toxicity of these gases, a gas mask is recommended. It can liquefy butane, a far less toxic, but highly flammable gas. Getting Homeless man's liquid nitrogen on skin can be deadly, as frostbite can occur. It's a cryogenic liquid.

Smart man's liquid nitrogen is dry ice mixed with 1,1-Difluoroethane. The boiling point of 1,1-difluoroethane is -11.29°F (-24.05°C) while it's melting point is -178.6°F (-117°C). The sublimation point (the point at which a substance sublimes, or goes from a solid directly to a gas) of dry ice (solid carbon dioxide) is -109.2°F (-78.46°C). Smart man's liquid nitrogen stays at around -78°C as long as you keep supplying more dry ice. Then the dry ice runs out and it heats up until it reaches -25°C where it becomes homeless man's liquid nitrogen. Then the 1,1-Difluroethane (can be found in computer duster) slowly boils away until it becomes gaseous 1,1-Difluoroethane. You can keep chemical reactions cool with smart man's liquid nitrogen and once it becomes homeless man's liquid nitrogen, you can use a funnel and a plastic soda bottle to store the liquid difluoroethane under pressure and label it and put it in the lab freezer.