San Juan 21 Class Association

Those plastic cups and caps that cover the nuts inside the cabin, what are they called and where can you get them?

Like these https://www.westmarine.com/buy/handiman ... 90_001_504?

In my experience, they are available at any hardware store... I use them under nuts with a metal washer, just use a larger size. This is not something that needs to be "marine" quality.