All sizes have an approximate 1/4" (6mm) wearable area and the backs are hollow.
Date posted: 3/22/2013
Just as described. No issues screwing on the back, and they feel no heavier than other steel screw fit tunnels of the same size.
Date posted: 12/24/2012
These are nice plugs, but I don't love the screw on back. It takes me a while to get them nice and tight when I first put them on. Plus, I only got these cause my boyfriend loves Superman - I'm a Spiderman girl myself = )
Date posted: 9/24/2012
only got these because i am in love with superman. but i hate the screw on. was too excited for them i didnt notice haha
Date posted: 8/20/2012
these are a bit heavier than i was expecting but overall, i they're still great!
Date posted: 8/15/2012
Image is clear even in small size. The back is easy to screw on and they stay well. Love them!