After three years experience — including packing at least 200 reserves, 100 each of two different types — Senior Riggers can test for the Master Rigger rating which allows them to do most major repairs. There is no written test for Master Riggers, but the oral exam is far more extensive, including identifying dozens of material samples. The Master practical exam starts with assembling and adjusting a sewing machine, then doing a major canopy repair that includes a seam, reinforcing tape and line attachment. Master candidates are usually asked to demonstrate a harness repair also.