The H zone of a myofibril contains

The A band consists of thick filaments and the I band consists of thin filaments. In a resting state, the edges of thin filaments partially overlap the free ends of the thick filaments in the peripheral parts of A band, except for a pale central part of the thick filaments. This central part of the A band, in which thick filaments are not overlapped by thin filaments, is called the H zone. Thus, H zone contains thick filaments but not thin filaments.