6 SPEED FREEWHEEL BLOCK 14/28 SCREW ON INDEX CASSETTE MTB ADULT OR CHILDS BIKENEW ALL BLACK FALCON 6 SPEED INDEX FREEWHEEL (SOMETIMES KNOWN AS A SCREW ON CASSETTE OR A BLOCK )SCREWS ON TO ALL STANDARD MULTI-SPEED REAR HUBSWE STATE IN THE HEADING ” SCREW ON CASSETTE ” BECAUSE SO MANY PEOPLE CALL THESE FREEWHEELS A CASSETTE BUT TECHNICALLY THEY ARE NOT A CASSETTE BUT A FREEWHEEL , IF IN DOUBT PLEASE ASKTHE TEETH ARE INDEXED TO WORK SMOOTHLY WITH MOST SHIMANO & ALL OTHER BRAND DERAILLEURS AND SHIFTERSIDEAL FOR REPAIRS OR REBUILD OF MOUNTAIN BIKES, ALL TERRAIN BIKES, TREKKING , KIDS BIKES ETC ETCTHE RATIO IS GOOD AS YOU CAN SEE THE LARGEST COG IS 28 TEETH GOING DOWN TO THE SMALLEST WITH 14 TEETHRATIO 28/24/21/18/16/14 (THIS IS NO OF TEETH ON EACH COG )VERY WELL RESPECTED BRAND “FALCON”420grams APPROX