Complete set of weights What's the difference between our F1 and M1 Weights: F1 are more precise than M1, with smaller permission error. F1 use 304 stainless steel, M1 use 2cr13 stainless steel. M1 are with adjust bar (at the bottom of the weights), F1 are without. F1 Grade 1mg-1Kg Stainless Steel Calibration Weight Kit F1 grade 1mg-1kg stainless steel scale calibraiton weights kit sets, balance weights. Total 25 pcs weights, use 304 stainless steel. Packed in aluminium alloy case, with factory’s certificate. F1 Grade 1mg-500g Stainless Steel Calibration Weight Kit F1 grade 1mg-500g stainless steel scale calibraiton weights kit sets, balance weights. Total 25 pcs weights, use 304 stainless steel. Packed in aluminium alloy case, with factory’s certificate. F1 Grade 1mg-5kg Stainless Steel Calibration Weight Kit F1 grade 1mg-5kg stainless steel scale calibraiton weights kit sets, balance weights. Total 28 pcs weights, use 304 stainless steel. Packed in aluminium alloy case, with factory’s certificate. F1 Grade 1mg-200g Stainless Steel Calibration Weight Kit F1 grade 1mg-200g stainless steel scale calibraiton weights kit sets, balance weights. Total 25 pcs weights, use 304 stainless steel. Packed in aluminium alloy case, with factory’s certificate. F1 Class 5kg Stainless Steel Scale Calibration Weight F1 class 5kg stainless steel scale calibration weights, balance weights. Material : 304 stainless steel. Permissible error: +/- 25.0mg. Packed in aluminium alloy case which has sponge inside to protect the weights. With factory's certificate of calibration. M1 Grade 1mg-200g Stainless Steel Calibration Weight Kit M1 grade 1mg-200g stainless steel scale calibraiton weights kit sets, balance weights. Total 25 pcs weights, use 304 stainless steel. Packed in aluminium alloy case