I have a large one, for my 29 gallons, but a hose is all I can use for my smaller tanks. However, I keep sucking up the gravel with the hose, blocking the hose, so I get irritated, agravated and I don't do a very good job of a substrate clean.
I had an idea, which I think can be reproduced to suite any size tank, even a tiny fish bowl. Works a charm.
Hose: pick your length.
Syringe: (booster size or larger or smaller if you use an air hose for the very tiny nanos) ask your dr or visit a vetrenarian. I used to have a large animal vet and buy these things when I worked at a farm. I still have a couple points kicking around...somewhere.. I use this for catching baby shrimp, fry or foods.
And a clamp thing: (optional)
Pigeon: not required, best left out as they easily get under foot.
The parts required. Dancing bird.
Seperate the plunger from the tube. Lose the plunger (although in very small systems it is great to start the syphon by yanking it out. Your choice)
Voila! Done, complete and likely very cheap. Get to those little tanks