Recommends are problematic with items that are SO subjective about if we love it or loathe it or wish we'd NEVER heard of it. My first real factory made "Colon Tube" that I remember details of- was a Red 20 Fr Davol about 20 inches long.
It took me three weeks to get at all comfortable in working it into anything other than a frustrating lower bowel *KNOT* that reminded me of tying a cherry stem in one's mouth. Pulling that knot out was a mix of exasperation and delicious sensations that have me stupidly grinning in memory of how my ass reluctantly birthed the thing. With MUCH more of an emotional whiplash than I'd had before or all that often since.
And then- one more time of getting into the headspace of simply _wanting_ it to be in me, I'd tried inserting it into a quite crampingly full gut as attempt of draining a STUCK enema.
The tube seemed to be snakelike seeking my deepest recesses and I'd almost had an orgasm over my whole bowel's length as I kept feeding more..more,,more till the nozzle&colon tube junction was in my hand. At that point- Opening the clamp and feeling my colon DEcompress was what triggered a soft warm almost -must be what some female orgasms could be... and I knew it was the *BEST five bucks spent in my life up till then.
Flash forwards to my reading this thread and the comments. You get what you pay for in custom items and mass marketed medical stuff comes in crap or hospital prices these days. Cheap- Quality- or make it yourself. Where the rules of Cheap-Easy-Good, Pick MAYBE 2 are up to your research/skills *so it's your literal ass on the line if you fuck up*
And for Shit's sake don't EVER contemplate making crap to undercut the folks who make Platinum Cured real safe&good things. .They have earned our money for their products. Though? if anyone wants to make the next generation of Colon snakes that might become legends- Go For it only if you are all in for the expense of Doing It Properly. And I might be a feedback tester too.
That Said? Pick from the few folks that have high feedback ratings among sincere users of that category.