Styrene profile sets gather several sizes of one section into a single pack, so you do not have to know in advance which dimension will look right on the model. Also grouped here are punch-out discs: sheets of pre-scored circles that you push out at an exact diameter and use as a flange, a cap, a washer under a bolt head or a round panel, without drawing a single circle with a compass.
Push the discs out with a thumb against a flat surface; if a tag is left on the edge, dress it off with abrasive paper. A multi-size set earns its keep mainly early in a build, while you are still judging the proportion of a part by eye. Once you know the dimension, individual shapes and sizes come from the plastic profiles, flat areas from the styrene sheet, and everything goes together with solvent modelling cement.
