Countertop blenders use a mixing container that holds 1 to 2 liters (1 to 2 US quarts).These containers can be made of glass, plastic, or stainless steel. Glass containers are heavier and more stable. Plastic containers can get scratched and may take in the smell of the food being blended. Stainless steel looks nice but makes it harder to see what’s happening as the blender works.
Most countertop blenders have 2 to 16 speed settings, but more speed choices don’t always mean the blender is better for everyone.
If the blades can be taken out, the container should have a rubber ring or seal between the container and the base to stop leaks. 
The container is shaped in a way that helps the ingredients move around the blades, not just spin in place.
The container sits on a base that has a motor to spin the blades and has buttons on the top to control the blender.
Many modern blenders have several speed options. Blenders with low power need some liquid to work well because the liquid helps move the solid ingredients around the jar, making sure they touch the blades. The blades make a whirlpool effect that moves the solids up and down, mixing them evenly. High-powered blenders can grind grains and crush ice without needing extra liquid.