The Bailey 1771 Lockfast Drop Scraper, 100mm/4in, is perfectly made to glide over small obstructions and it drops into a vertical scraping position to allow offending material to be dragged back towards the operator, to make to job much tidier. Use with Lockfast Drain Rods. Specification: Size: 100mm (4 in). The Bailey 1771 Lockfast Drop Scraper, 100mm/4in, is perfectly made to glide over small obstructions and it drops into a vertical scraping position to allow offending material to be dragged back towards the operator, to make to job much tidier.