These are top quality EPDM Rubber stoppers. There may be cheaper stoppers out there but these are my first choice. Perfect fit and stopper softness. Another feature I love is that the stopper SIZE number is molded into most of them. My latest order did not have this feature. I hope WidgetCo corrects this. This is a real time-saver plus, knowing what size I have. WidgetCo carries many items that can be difficult to find. Great all round service. Highly recommended.