Since some of you managed to damage the first batch of 100% seal, the second made of a different material. In theory it it less flexible and prevents the lips getting caught by the nozzle.
Still, the correct carefull assembly is crucial for correct function.
Until the stock last of first batch (last 70pcs) both those and one of these will be included in one package. After that only one of the second batch.
The cost remains the usual 10$ each.