A lot of threads talk about caves and there different dimensions, but i have found my plecs like these as well.
They were made to give females and sub-dominant plecs somewhere to hide, for the ones that don't claim a cave.
This is not meant to be a zebra picture thread, as all my hypancistrus use them, just seem to mainly have pictures of my zebras using them.
It was after propping up slate like the picture on the right, i decided to try to make some better ones.
I used to make a back for them, but that was O.T.T., all you need to do is push one end up against a tank wall.
If they are siliconed well, they are solid.
In a tank i had a pair in, the female used to hide under the slate, or on top of the slate under the wood.