I have the Storm Rolling Thunder 4 ball roller. It's great and like having 2 bags in one. You can take off the top and just use the shoulder strap to carry 2 balls, or keep it attached for 4 balls. It is very easy to take the 2 apart for loading/unloading purposes, so you don't have to pick up 75# at one crack. Plus, if need be, when you pull up the handle to pull the bag, there is enough space on there to add a Joey bag as well, making it a 5 ball bag! I recommend this bag, though one of the carry handles broke when my son pulled his one ball bag out of the trunk of my 4Runner, making the bottom half of my roller to fall to the ground, breaking the handle. A quick email to Storm and they sent me a new handle, free of charge, within a week.