What is correct toilet supply line

[Buzzer]

Hi. I need a new toilet supply line but don’t know the size type of the fitting at the shut off valve. It is not 3/8 compression. It is a plastic nut about the same size as the one going into the cistern but has a different thread. Attached is a photo. Can you advise. Thanks.

 

[Stigster]

It reminds me of a washing machine hose which is 3/4". Could it be the same size as that? It's hard to get the scale from the picture.

 

[ShaunCorbs]

https://www.homedepot.com/p/BrassCraft-3-8-in-Compression-x-7-8-in-Ballcock-Nut-x-12-in-Braided-Polymer-Toilet-Supply-Line-B1-12DL-F/100094502