The Do it Metric T-Handle Hex Key Set includes 8 pieces made from chrome vanadium steel. The sizes in the set are as follows: 2mm x 3 inches, 2.5mm x 3 inches, 3mm x 4 inches, 4mm x 4 inches, 5mm x 6 inches, 6mm x 6 inches, 8mm x 8 inches, and 10mm x 8 inches.