This really isn’t a vise in the conventional sense, but it calls itself one, so I’ll allow it. The idea is that if you slip a board through the appropriate opening, then press the plate sideways, it will lock in place firmly enough that you can use it as a cutting guide for a circular saw. You can even use it as a small sawhorse, supporting the weight of the board as you cut it (with the weight providing the twist needed to keep the “vise” in place).
Location: Floor
Have you used this tool? Think my description is all wrong? Have a better example? Comment now with any thoughts you have about this tool!