The quality makes a decent impression and the price corresponds to the original Miele bags. The Miele bags are a bit thicker and inside there are some extra plastic filter layers in the bags. So far these ZVac bags seem to be doing the job. The bags snap on fairly tightly, and the spring-loaded valve has a nice rubber collar that makes for a good seal with the hose. I have found that there is slightly more resistance when closing the lid for the vacuum as the collar is pressed against the hose inlet. The spring-loaded valve does not close 100%, but keeps most of the dirt out well.