Medium straight block text (Type B / Mittelschrift) technical stencils - letter heights 3.5mm, 5mm or 7mm.  The "H" construction lifts the stencil cut-outs off the paper to avoid smudging and raised edges slot neatly against a T-square or ruler.   Strictly adheres to ISO 3098/1 and DIN 6776 standards for technical drawings and microfilming.