Like many other people, I bought this to make a guinea pig enclosure.
I bought three sets of these to make a 5x2 pen with a stand and two lofts, one at each end.
The round connectors are very secure but are difficult to properly clip into place; using a pair of pliers worked very well though to pinch the grids into the connector.
I got the accessories from Grendle and the correx through Grendle and I know my boys will be very happy in their new home. 
It's not possible to get something this perfect from a pet store and even though it takes time to buy everything needed, plus having to build it all, it's worth it to have the freedom to choose the size as needed.
The covering I used on the outside of the correx is vinyl type stained glass effect on a roll that I bought from Amazon. I'm so happy with the effect.
So happy I found the grids on Wayfair, this was the first time I've shopped on here but I will definitely be shopping here again.