Hello Customer, The gasket is standard gasket that is used by most pop-up drains and is approved/tested by IAPMO for plumbing code. Since the gasket thas to be pushed into the entry hole at the bottom of the sink, sometimes it could be a bit tedious depending upon the configuration of the hole and the skill of the person installing the drain. In such situations, please contact us at sales@pfwaterworks.com so we can provide appropriate guidance and assistance. Thanks.