Staedtler Masterbow Comfort Student Compass for Circles to 10.25 Inch Diameter, Lead and Pouch (551-40-WP) Reviewhttp://tinyurl.com/n6jypeu Staedtler Masterbow Comfort Student Compass for Circles to 10.25 Inch Diameter, Lead and Pouch (551-40-WP) Prevents unintended setting adjustmentsMaximum circle diameter is 10-3/8'' (265 mm)Includes a spare lead tube and comes in a plastic walletSize: 3-1/4"W x 1/2"D x 7-1/2"L