There’s no need to panic if you drop something down the sink. Scott Cam explained that your wedding ring or valuable item is probably still in the S-bend (S-shaped water trap in the pipe).
Before unscrewing the S-bend, try pulling the lattice filter out of the sink well (many sink models have ‘pop out’ filters) and using a piece of wire to fish out the item.
If you can’t retrieve the item using a piece of wire, you’ll have to unscrew the S-bend (keep a towel handy to mop up any drips). Plastic (PVC) S-bends are easy to unscrew, either by hand or using a set of multigrips. However, a set of stillsons may be required for metal pipes.
When reassembling the pipe, ensure that the washers are set in place.