Manfrotto makes a well-thought-for and well-designed sandbag; Arri does not.
Manfrotto sandbag actually keep the sand in all the time, in transit or in use; Arri leaks sand through the zipper … all the time.
Manfrotto uses better material for their sandbag; Arri, well, let’s say if rain starts to fall, water will soak through the bag easily.
Manfrotto … just go buy a Manfrotto sandbag if you get a chance and stay away from Arri’s.
If you have a better suggestion, I am all ears.
yours truly