As the picture show : Red No.1 Rubber sealing stripe ，Acturally we call it Flange U sealing strip ，It is Fully enveloping the perimeter of the screen .But Red No.2 show ：Not completely covered .
Red No .1 solves prolem from Two points are reflected .
- Complete solve the Powder leakage problem .
- Increase screen using life .
As so far , Food/Medicine Grade have been applied to this .