The Zet boats have a range of spares and accessories available for when yours have been used and abused and need replacing!
If you have just lost the bung but the rest of the fitting is still there, then this is the right plug for you, as long as your boat is a Zet! Plus it's better than stealing somebody else's!
A drain bung can be deceiving, although it looks small and insignificant it is probably one of the most important items to have, without this bung in your kayak or boat it is going to allow water to flood into the boat and then kayaking will have to be abandoned.