The preformed coconut liner keeps your window box neat and tidy inside, and connects it to nature outside. These coco liners create a ���down-to-earth" feel and enhance the planters�۪ connection with nature. They keep the aesthetic design of the planters from being spoiled by unsightly roots and dirt, but still produce the effect of a natural growing environment. This liner will fit the 42" Charleston Wall Trough which measures approximately 42" Long x 9.5" Wide x 10" Deep Important: Please measure your existing window box to ensure that these liners will fit. These Coco Liners are sold only as a set of 2.