𝟑𝐦𝐢𝐧 𝐢𝐧𝐬𝐭𝐚𝐥𝐥𝐚𝐭𝐢𝐨𝐧, 𝟑𝐬 𝐫𝐞𝐩𝐥𝐚𝐜𝐞𝐦𝐞𝐧𝐭: This under sink water filter system works perfectly with 3/8” and 1/2” cold water tubes. The under sink water filtration system is a simple DIY.