I get my hides at the hardware store!
They're PVC LB Access fittings, you find them in the electrical aisle. They have sizes from teeny wiggleworm to huge fat BP (but the biggest size is special order... and kind of expensive!)
in the picture it's "upside down". Take off that screw-on panel and put it down in the cage. I find my snake enjoys entering/exiting through both top and bottom at times... sometimes he comes out the top and goes in the bottom!
