it doesn't have to support the loads of fishing, i.e., doesn't need to be strong, so I they could get the action they want using graphite.
but don't know the actual answer

I have one of the original indoor practice rods, Its fiberglass and uses yarn as the line. I had fun with it and it is practical as a practise rod. It will help you with timing as well as help you learn to tighten your loop. I took it to work and would play with it in the office. My boss didn't like it , but what I did before work and during my lunch was none of his business. But a number guys tried it and had fun playing with it. I even taught 2 guys how to cast with it and they still fly fish today. But I have to say I don't know much about the one sold by scientific anglers. But you may find it works for you.

They can help a beginner learn to cast a line rather than throw a weight off the end of a pole. And a cat is a good assistant. Having said that, I'd just go down to a discount store and buy the cheapest 9 foot fly rod I could find, probably $15 this time of year, or to a junk shop and pay $5 for one. Choose it as a usable beater/back-up rod. It's tip section, 4 1/2,' will work just fine. Fashion a temporary grip from any old tube or foam pipe insulation. A spool of heavy mason's twine and a scrap of yarn or ribbon and you are in business. My grandson, age 4, already forms a beautiful loop with one, opens or closes it as we decide how he wants the loop to look, and lays out a nice straight line. He did break one when the cat struck the yarn too hard and he reared back like Charlie Moore with a flippin' stick.

I've used a rod tip and yarn for years but a more compact choice for me now is "The Accelerator" Fly Casting Trainer. The Accelerator is an ingenious device comprised of a plastic tube containing a ball bearing (and a simulated rod grip) that provides imediate feedback, through the action (& sound) of the ball bearing moving in the tube.

It may be available through Feather Craft or from the inventor, Floyd Dean through dean4fish@aol.com.

FWIW - Lee Wulff was peddling those things back when Theodore Gordon was in knickers. We made our own by just using half of any rod we had handy since in those days, most rods were 2pc.

Here's Lee's version: http://royalwulff.com/products/royal-wulff-fly-o/

The Lee Wulf one is the one I Have. I got it when they first came out. They were made by Garcia if I'm not mistaken. Not quite as old as when Theodore Gordon was in knickers but more like when he got his first dry flies from Halford.

They're great for dog fishing...

Years ago I had a thin stem of black stem bamboo, about 3' long with around 8-10' of heavy green garden twine for a line. Worked remarkably well. It would even roll cast on a tile floor. Who needs a fancy, name brand practice rod !

You've gotta just put the screws to them. Sure, you may lose a few, but usually both cats and dogs are repeat biters...although cats will spook easier.

I've never tangled with an Italian Greyhound....bucket list worthy for sure.

at least we're having fun yet

Better to see some humor vs. typical cranky off-season arguing.

It's currently 12˚F here and we're waiting for a forecasted 6-9" snowfall to start in a few hours. I'm hoping the snow and cold weather that's supposed to follow it will freeze up my favorite lake so I can do some ice fishing next week. That's how I get my fishing fix in the winter.

When I got my first fly rod as a teenager (on sale in a local hardware store in the middle of winter), the first place I mounted up a reel and tried casting it was on the frozen surface of Lake George, NY.