Flyweb Replacement Glue Boards are to be used specifically with the Flyweb Fly Light. These easy-to-use, non-toxic glue boards trap up to 100 flies. To activate the glue board, simply peel away the protective plastic film and insert the board into the inside slot in the back of the Flyweb Fly Trap. Once a glue board is full, discard it and install a fresh board. Glue boards are safe to handle and easy to replace. Glue boards measure 3×5 inches.