Like the Monochrome blocking pins, these blocking pins have more than one pin per strip, making blocking wide-width projects easier, but come in beautiful rainbow colors! The Anchor holes in each blocker allow you to attach a string along the longer side. which can be pulled to maintain even tension. Blocking pins are made of durable plastic, with rust-resistant pins, knit blockers help you to expertly finish your projects. Each Pack contains 20 Knit Blockers (12 Knit blockers having 8 pins & 8 Knit Blockers having 4 pins).