Indications: - Debridement and cleaning of the root canal. - Removal of all infected and affected dentin. - Smoothing of the canal walls. - Tapering of the canal to receive a filling. Advantages: - Exploration and access to the orifice. - Gives straight-line access to the canals. - Achievement and maintenance of apical patency. - More flexible. - Corrosion-resistant. Specifications: - Size: #45-80. - Length: 25 mm. - Material: Stainless steel.