Fastcap's ProCarpenter family of tapes are manufactured with several innovative features that were developed from in-the-field use by professional woodworkers and cabinet builders. The PMMR-FLAT16 is a great example. The limp, flat design of the blade allows it to sit flat on the surface you are working on, allowing for precision marking without having to tip the blade. The metric/metric reverse blade has markings on both edges for left or right handed marking.