I will here remark, that having a dry type fire extinguisher mounted vertically can cause some problems. The dry chem can and will settle and over time actually pack in the bottom of the canister. And if ,gawd forbid, you need it all you might get is a puff of retardant and a huff of gas. So if you mount one vertically on some thing that vibrates like a tractor, then it is a very good rule of thumb to remove it and turn it up side down several times when you check the gauge, thus loosening the dry chemical inside. This is something I was taught by Kidde way back in the day, also there has been a huge recall on some extinguishers just recently. So you might want to check on that as well