What Niro-Dreams sells on eBay, I would call a DIY self-bondage stainless kit. Various M8 mountable dildos (I like 18x4cm one), enema nozzles (4x20cm!), telescopic poles, etc. Of course, you can use the steel dildos “standalone”, but the pole bring the whole experience to the next level.
One of my bondage and self-bondage dream scenarios is to be held in place by a dildo on a stand or a pole mounted to the floor. You straddle the dildo, make the pole longer and you can’t go anywhere!
See also: Bondage on eBay – interesting finds forum thread.