I got a small nitrogen bottle with gauges and hose to charge off road racing shocks. Portable, can get to higher pressures for those units that need it and economical as you can recharge 20-30 mufflers on a single bottle. I checked with MEI before hand and they said nitrogen was perfectly fine to use to charge their mufflers. I also recommend getting a hard sided case like a Pelican or Apache or small hand truck to strap it to. I hope this helps.