In order to run properly, every decorative fountain must be leveled properly. Aquascape Fountain Shims are ideal for leveling a wide variety of water features and fountains including resin, concrete, and GFRC water features. Durable plastic construction makes these shims impervious to water damage and allows the shims to be stacked when necessary. Shims measure 4.5 inches by ¾ inch. Six easy-to-use shims included.