1. Buccal tubes
Rectangular buccal tube of 0.018x0.025 inch are used.
Types include :edgewise buccal tube, cast and machined buccal tube, combination buccal tube, triple buccal tube
Buccal tubes (round) are inch internal diameter and inch length.
Flat oval buccal and double back arch wires are used in certain situations like..

2. Placement of molar tubes
They should be parallel with the occlusal surface when viewed from buccal and parallel with a line bisecting the occlusal surface of the tooth mesiodistally when viewed from occlusal