Staedtler Advanced Adj. Cntr Wheel Student Compass - Back to school! Advanced student compass includes center wheel that adjusts quickly and easily. Design features resilient sand-blasted and nickel-plated metal parts, nonslip grooved grip and hinged lead and needle legs. Leg extensions are plastic. Compass is equipped with a high-quality metal universal metal adapter for easy circle-drawing with all writing instruments. Maximum circle draw is 10-1/4 (26cm). Compass includes spare lead tube with extra 2mm lead.