*IMPORTANT! PLEASE SEE THE SIZING CHART INFOGRAPHIC BEFORE BUYING. MID WEIGHTS DO NOT FIT MOST HEX STYLE DUMBBELLS UNDER 25 LBS. AND MOST ROUND STYLE DUMBBELLS UNDER 10 LBS.* PRECISELY WEIGHTED: our 4-Piece weight add-ons for dumbbells contains four 1.25 lb micro plates that were designed with accuracy in mind with a tolerance of +/- 6 grams. Expertly crafted for a secure fit on most dumbbells, these micro weight plates were made to enhance your existing fixed end dumbbell and barbell sets. Apply one weight for a 1.25 pound adjustment or complement with another plate for a full 2.5 lb increase for each dumbbell.