Water polo water injection assembly and water polo water injection device

A water injection assembly for water balloons, comprising:

• a connecting part provided with a first water inlet channel configured to be connected with an external water pipe or an external water injection cylinder;
• a water injection seat, provided with a plurality of outlet holes and an injection tube bundle including a plurality of injection tubes communicating with the plurality of outlet holes;
• a conversion seat, provided with two opposite clamping grooves, a shape of the water injection seat being adapted to an area of an opening surrounded by the two clamping grooves, and the water injection seat being capable of being just inserted into the two clamping grooves;
• wherein the area of the opening enclosed by the two clamping grooves has a structure in which opposed ridges act to hold the water injection seat in place while providing a narrower opening for the injection tubes to pass through;
• a small end of the opening is capable of being used for the injection tube bundle to pass through;
• the first water inlet channel is connected to a large end of the opening;
• when the water injection seat is inserted into the two clamping grooves, a water flowing out of the first water inlet channel flows into the injection tube bundle through the outlet hole.