Create openings for pipe in your poured concrete using wall sleeves like this 8" sleeve from Century-Line. This is an all plastic sleeve that weighs in at about an eighth the weight of comparable steel sleeves! Installs easily before pouring and can be used in conjunction with Link-Seal modular seals.Model: CS-8, Material: HDPE, ID (in.): 8.21, ID (mm.): 208.5, lbs: 4.8, Kg: 1.63