This tool trims excess carpet at the wall leaving just the right amount for tucking between the base board and the tackless strip. The deluxe trimmer has top-loading blade carriers that make blade changes faster and easier. The wide open throat area allows carpet to enter and flow smoothly to the blades. This reduces wadding of carpet and resistance to cutting. Comes with six shims for adjustment of cutting height and four throat adjustments for different carpet thicknesses. Wall runner is angled outward to minimize wall contact and includes a replaceable wall protector pad to prevent marking