A monolithic transparent plate including, on at least one of its faces, at least one region textured by a plurality of geometric features in relief relative to a general plane of the face, each feature having a cross section, parallel to the general plane, which diminishes with distance from the face, from a base to a peak of the feature. Certain aspects provide methods and apparatus for wireless communication by a device capable of communicating in at least a first and second RAT networks. The drill bit is provided with a plurality of blades protruding from the drill bit and, a plurality of flow channels stretching along the drill bit in a substantially radial direction whereby the successive flow channels are formed between two adjacent blades.