I love these for several reasons; the color match helps match the lids to the correct container and the locking sides really provide a definite feel for sealing the container. Flip them down and it pops into place with a sound and a feel that verifies they are closed and sealed!  These are also a thicker wall container and lid and this is great for my leftover foods or to take food to work and microwave, or even eat cold. To me this flip lock system is like a step above regular press fit tops.