What is this washer called?

[onionsa]

I need to replace a washer that fits an appliance outlet at the sink trap. It got distorted on a bad install as can be seen in the pics. Ideally I’d like to replace with another flap type one but nothing I search for brings them up. This is bigger than a 3/4 inch pipe washer from the water feed.

Is there a special name for them?

Thanks in advance.

 

[Bodgedbuild]

not sure you can buy that separately, but the entire appliance nozzle is very cheap..
https://www.diy.com/departments/floplast-appliance-nozzle-dia-40-mm/537127_BQ.prd

 

[onionsa]

Thanks for the reply. Ended up buying a replacement adapter like you have suggest

 

[jj4091]

sink trap backflow washer