The lids have four folded tabs that locate beneath the rolled rim of the pot, this prevents the lids from displacement by boiling or wind effects.
No vent holes are needed because of the lid seating on top of the rim, not internally engaged with the pot. the lifting tag is a poly. cable tie, which does not attract the transfer of heat.
The lids are recommended for pot diameters between 80 – 150mm and for a level top rim without pourers or spouts. Weight will vary from 4- 8 grams, depending on diameters.