NO8 Manual Post Drivers If you have never used one of these, they are real time savers. To use it, you slide it over your sign post and then you stand it (and your sign post) upright. Then, simply pick up the heavy (38 lb) driver and drop it. Each time you drop it, it will drive your sign post a little deeper into the ground. The 65" length (on the Model NO8) permits one man to drive posts as high as 12' from ground level. The manual post drivers are available in two different models. Get model "NO8" for use on u-channel, round and square posts (Barrel ID = 3-3/4")..