Crimped bristles wash easily and prevent gathering of mold and mildew. Split shape is efficient for cleaning flat surfaces, under counters, around equipment and along baseboards. Hi-Lo Floor Scrub provides maximum cleaning at 3 different angles. Base resins used to produce blocks and bristles are made of FDA approved materials. BPA free. Threads are 3/4-5 ACME. The standard thread form in the US. Handles sold separately. 1 each