Hi, we're sorry to hear that you had an issue with the fit which caused you to not have a great experience with our Elkay LKQS35GY Polymer 3-1/2" Drain Fitting with Removable Basket Strainer and Rubber Stopper. Thank you for letting us know about your experience. It is our priority to ensure customer satisfaction. This model is a drain and strainer basket designed to work with a standard 3-1/2" drain opening. The strainer flange is placed into the drain hole from insides the sink bowl with the gasket and drain body being installed from the underside of the sink. There is then a ferrule (bolt) that is tightened down from the top through the strainer flange and into the drain body to hold it in place. The drain tubing then attaches to the bottom of the drain body with the supplied washer and nut. I have also included the direct link to the installation instructions. Please contact our Customer Care department by phone at 800-476-4106 or email at productsolutions@elkay.com as we would like to discuss the matter in more detail and can help with any installation questions you have.
https://images.thdstatic.com/catalog/pdfImages/06/068a015a-7979-43e0-a812-0db8c9dfacc8.pdf