I use a 3-gallon, wide-mouth garden sprayer by Chapin. They're available many places online. I cut the pump out and sealed up the resulting opening with a PVC cap and silicone. I installed a presta valve in the hose (cut short) with a hose clamp to secure it, and I use a bicycle pump with gauge to pressurize it. It holds 49-50 balls. The balls won't flow out the opening, but I can reach my largish hands inside and pull out two balls at a time.