Amazon.com : BIC Velocity Original Mechanical Pencils, Medium Point (0.7 mm), Assorted Colored Barrels, 4-Count Pack, Pencils for Office and School Supplies (MV7P41-BLK) : Office Products
Mechanical Advantage , Velocity Ratio and Efficiency - YouTube
Bic Velocity Medium Mechanical Pencils 0.7mm, Assorted Colors 2 ea (Pack of 2) - Walmart.com