The Nyoibo aka as the Power Pole, is a weapon in the beginning of Dragon Ball series which young Goku often carry around. Handed down by Grandpa Gohan, Goku wouldn't let it leave his side.
The Nyoibo is a red wood-like magical staff which can grow any desire length by verbal command of the owner. The origin of the Nyoibo pole however was a pole which connect Korin tower to Kami's lookout.
As for the toys, toy maker came out with a number of it.
This Nyoibo toy can extend to extends to 50cm which also add up as a Marker.
Another "life size" by bandai. You can twist and turn the Nyoibo like Goku did!
Personally I prefer the pole of monkey king in the "Journey to the west" novel that come from the deep sea.