the SL- 3 and its bigger brother the SL-5 are the preferred choice of vacuum cleaners for carpeted and hard surface floors. If you have cleaners who need to get in and out on a cleaning job quickly and they’re, shall we say ‘very rough with equipment-these Centaur vacuums are just the ticket And talk about sturdy wear and tear ability we’ve seen the SL-3 getting thrown around, tumble down stairs, and dragged on airport tarmac until the round casters become FLAT… and still keep working When you arm yourself or your cleaning staff with a St-3 or St-5 vacuum, you know you’re sending them into battle with the best, most rugged vacuum cleaner on the market that’s guaranteed to never let you down!