G‑Floor Center Trim is a 4” wide double-slotted polyvinyl strip, meant to join the sides of two mats together and cover the edges for a more finished look. Center Trim will allow adjoining mats to ‘float’ and prevent buckling during temperature changes. After insertion into the center trim piece, be sure to leave an inch of room on both sides. More on G‑Floor Center Trim here: https://bltllc.com/gfloor-universal-flooring/accessories/