18" Poly-Pro Flower Box Planter Liner - White Keep your flower boxes lasting season after season Use as liners inside of wooden planters or wire hangers Limit rot and rusting caused by water damage Liners consist of traditional, raised-panel plastic and include knockout plugs for drainage Choose from four sizes: 18"L x 8"W x 5.25"H, 24"L x 8"W x 5.25"H, 30"L x 8"W x 5.25"H, or 36"L x 8"W x 5.25"H (Exterior Dimensions)