This 63mm white polypropylene (P/P) buttress style continuous thread closure has a ribbed skirt and a flat top. It includes a .040 inch foam liner.
A foam liner is a general purpose economical liner. It remains in the closure during repeated opening and closing of the package by the consumer to provide leak protection. A good choice for household chemical and water based products.
Note that a Foam liner does not provide the consumer any indication of tampering (tamper evidency).