I went out & made a special trip to pick up more material for the inserts on the new freestanding tunnels, & luckily I took good notes so they are just about ready for sale now. The size you see is 12"L x 9"W & 5"H at the peak. My gut tells me that it *might* fit one not too big guinea pig, but perhaps a guinea pig owner can confirm that for me. The design, however, looks like it would upsize well & sturdy, so I'll just need to figure out where to source larger pieces of thin/pliable plastic sheets & I'll be able to offer those as well (any ideas, shoot them my way).
They'll definitely work for rats though, and I love that there is no padding to worry about. They are also easy to make, so they shouldn't be uber expensive other than figuring out the best way to ship them. If we can get away with a flat envelope & some bubble wrap around the insert, these should be pretty reasonably priced. :dance:
@ temblabamomo: I'm so glad you like them. I wasn't sure on the Rocky/Bullwinkle fabric (as not everyone is a fan), but I was simply dying to use it!