Seam Cutter Plus excels on carpets with zig zag ("hydra-shift") tufting including commercial loop pile and Berber carpets. The blade runs directly behind the center row guide. This keeps the blade away from the offset yarns at the hydra-shift "stopovers". This prevents the yarns from being sheared, which can cause unsightly seams. The wide base keeps the blade perpendicular to the yarns, further preventing shearing. The tool can also be used as a trimmer for precisely trimming carpet up to Z-bar or vinyl molding. For Z-bar, retract the row guide and the seam cutting (slotted razor) blade, and install standard utility blades on the back side. The outer edges of the base provide variable guidance for trimming the right amount of carpet to tuck under the Z-bar, based on the thickness of the adjacent flooring. For vinyl molding, retract the row guide and slotted blade, remove a portion of the base, and install utility blades on the back side of the cutter. An interior slot positions the utility blades so they leave the right amount of carpet to tuck beneath the vinyl molding.