We purchased these clear plastic mats to place underneath the cloth placemats (18.5" x 13") on our wood-topped dining room table. Because the plastic mats have an actual size of 17.5" x 12", they fit completely under the cloth placemats. The plastic mats did not move around at all on the tabletop during normal dining use, and the cloth placemats stayed in place on top of the plastic mats. We wanted plastic mats under the cloth mats so that condensation wetness from drinking glasses would not seep through and create water spots on the wooden tabletop. These plastic mats worked absolutely fine for this purpose. These plastic mats have enough thickness to be semi-rigid but are virtually unnoticeable when underneath the cloth mats. Thus, they worked out just as we hoped, providing protection for the tabletop without being noticeable during meals.