Strait-Line 1932877 IRWIN Mach6 Chalk Reel, 100' Easy Fill & Lock Top - Large, 1/4-turn locking top for quick chalk fill and easy access to reel internals - Easy fill & lock top 100' Hi-Tensile Line - Stronger for fewer breaks and for use on rough, abrasive surfaces - 2.5X stronger than traditional chalk reels 6:1 Gear Ratio Rewinds line 6X faster than traditional chalk reels Open Access Back Panel Allows for quick line change and cleaning Metal Drive Gear Resists gear failure under heavy load