Radius Marker, Medium, 50 in Circumference no checkout the extractor's grip increases Extractor size the extractor's grip increases Extractor size and recommended drill bit size are etched on each tool and fit Good dexterity and comfort the three smaller models will fit conveniently into a shirt pocket All have sturdy friction joints to maintain rigidity and accuracy Precision tools made of rust proof aluminum and anodized for lasting protection The arms are precisely aligned with spring tension joints to guarantee accuracy and rigidity The holder accommodates flat or round soapstone and pencils All are a folding type design