4 Pics 1 Word Level 759

Answer:
Supply
Hint
What is the answer to the 4 Pics 1 Word level with An old army truck, A blue water pump with a bucket under it, Grey arrows bending in to blue squares, and A wire plugged into something white?

Hint
What is the answer to the 4 Pics 1 Word level with An old army truck, A blue water pump with a bucket under it, Grey arrows bending in to blue squares, and A wire plugged into something white?