I recently jumped on the air train. Like last week. I currently have a FX impact M4, Notos , and am ordering a Huben GK1 today. Also, I purchased a GX4-I and a 6.8L tank from Air guns of Arizona. We live on ranch in West Texas and pretty much patrol the ranch nightly. Wither it be changing irrigation in fields, Varmint hunting with friends or my 4 kids. We have quite a few ranch vehicles. We also have a home gun range setup for pistol and LR and either my kids or I are their every day. We shoot burners alot... Having all this in mind, I am worried about having air supply handy. I would like to get some more tanks setup where I can mount them in some of the ranch buggies and maybe one at the range. How many of you that are filling at home worry about the DOT certification? My 6.8 L has it. But I see several on ebay etc. for half the prices that are only CE certified. I realize i would lose the ability to have a shop fill it. But i intend on buying a larger twin compressor for larger fills soon. Just wondering if it's worth the extra money for the DOT stamp in my case. Thanks!