The revolutionary Edge Files X7 uses our own flexible FireWire NiTi forged with our proprietary heat-treating process. The FireWire NiTi alloy improves strength and flexibility. Specifications : - Parabolic cross section. - Highly flexible. - High strength. - Length: 25 mm. - Taper : 4%. Pack contains: - 2 x #20. - 2 x #25. - 2 x #30.