A slip-lid case is also referred to as a “clamshell” road case. These transport cases are designed for easy handling, usually by one person depending on the case size. Examples include large screen cases, telescope case, gym equipment case, line-array system cases, large A3 printers, etc. By having the lift off lid split into 2 halves,  the lids can be removed from the sides, instead of over the top. As a result, in most cases what would be a 2 people operation can be achieved by 1 person. In some cases, 2 people operations can be dangerous or difficult when the cases are large or tall.