Child Resistant Caps, also known as "CR" caps, have all of the same basic characteristics of standard caps except for the requirement to press and turn the closure in one continuous motion to open. Resealing the container requires one continuous turning motion as does a standard cap. The top of a CR cap has raised letters with opening instructions and therefore cannot be printed or decorated. Foam liners are commonly used with these caps. A foam liner has a thin low density foam ring, which is sandwiched between two layers of low density polyethylene (LDPE) film. Foam liners are a good choice when chemical resistance or low moisture transmission is important. They also help protect against odor transmission and do not impact the taste of food products in the container. Foam liners are often referred to as F-217 or Sureseal liners.