STEVE, I DO WORK ON THE SIDE FOR A FRIEND OF MINE WITH A LARGE FARM AND A COUPLE DOZEN PIECES OF J.D. EQUIPMENT WITH A/C. AROUND 3.5 LBS OF 134A WILL BE FINE. I COULDN'T GET SPECIFIC INFO ANYWHERE ON WHAT THEY HOLD BUT THEY AREN'T REAL FUSSY WITH CHARGE WEIGHT... Login to read more.