These glass head pins never snag delicate silks or cottons. They are sharp, smooth pins with a fine .4mm nickel-plated steel shaft and excellent resistance and strength. Each pin measures 1 3/8 inches in length and wonderful for pinning! Glass heads won't melt when ironed over. Each box contains 150 pins. Watch the video tutorial below for how April uses these pins along with the Featherweight Accurate Seam Guide.