Rivet for crock or crockoff 

(you know, like a knock-off crock… crockoff… get it? 😆 sorry ill see my self out)

As a heads up:

The design is intentionally snug and made for use with PLA. 

It isn't too tight to use, but it might feel a bit stiff initially and the post can be a little difficult to pop in. Both are intentional

the post is tight so it won't easily pop out, The sandwiching between the crock and the strap is tight, so over time, as you wear the crock, the PLA will wear down a bit and allow the fit to move freely and become perfect for your crock. 

So, don't worry if it feels a bit tight at first it will loosen up and fit better as you wear them.