Bat structure having double-nested-tube construction

A bat structure having a double-nested-tube construction, comprising:

• an outer tube having a hitting section with a uniform outer diameter, wherein the hitting section has an end provided with an end cover and an opposite end provided with a tapered section having a gradually reduced outer diameter;
• and
• an inner tube integrally formed of a carbon fiber material, wherein the inner tube has an end provided with a handle section, the handle section has an end provided with a connection section having a gradually increased outer diameter, the connection section has an end provided with an insertion section having a uniform outer diameter, the inner tube is inserted in the outer tube, the connection section of the inner tube is connected to the tapered section of the out tube, the insertion section is peripherally provided with an annular raised portion, and the annular raised portion has an outer diameter greater than the outer diameter of the insertion section of the inner tube.