Head Protective Devices: Personal devices for protection of heads from impact, penetration from falling and flying objects, and from limited electric shock and burn.Respiratory Protective Devices: Respirators to protect individuals from breathing air contaminated with harmful dusts, fogs, fumes, mists, gases, smokes, sprays, or vapors.Protective Devices: Devices designed to provide personal protection against injury to individuals exposed to hazards in industry, sports, aviation, or daily activities.Ear Protective Devices: Personal devices for protection of the ears from loud or high intensity noise, water, or cold. These include earmuffs and earplugs.Eye Protective Devices: Personal devices for protection of the eyes from impact, flying objects, glare, liquids, or injurious radiation.Hearing Loss, Noise-Induced: Hearing loss due to exposure to explosive loud noise or chronic exposure to sound level greater than 85 dB. The hearing loss is often in the frequency range 4000-6000 hertz.Filtration: A process of separating particulate matter from a fluid, such as air or a liquid, by passing the fluid carrier through a medium that will not pass the particulates. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Occupational Exposure: The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation.Head: The upper part of the human body, or the front or upper part of the body of an animal, typically separated from the rest of the body by a neck, and containing the brain, mouth, and sense organs.Head and Neck Neoplasms: Soft tissue tumors or cancer arising from the mucosal surfaces of the LIP; oral cavity; PHARYNX; LARYNX; and cervical esophagus. Other sites included are the NOSE and PARANASAL SINUSES; SALIVARY GLANDS; THYROID GLAND and PARATHYROID GLANDS; and MELANOMA and non-melanoma skin cancers of the head and neck. (from Holland et al., Cancer Medicine, 4th ed, p1651)Device Approval: Process that is gone through in order for a device to receive approval by a government regulatory agency. This includes any required preclinical or clinical testing, review, submission, and evaluation of the applications and test results, and post-marketing surveillance. It is not restricted to FDA.Head Movements: Voluntary or involuntary motion of head that may be relative to or independent of body; includes animals and humans.Femur Head: The hemispheric articular surface at the upper extremity of the thigh bone. (Stedman, 26th ed)Equipment Design: Methods of creating machines and devices.Protective Agents: Synthetic or natural substances which are given to prevent a disease or disorder or are used in the process of treating a disease or injury due to a poisonous agent.Intrauterine Devices: Contraceptive devices placed high in the uterine fundus.Equipment Safety: Freedom of equipment from actual or potential hazards.Sperm Head: The anterior portion of the spermatozoon (SPERMATOZOA) that contains mainly the nucleus with highly compact CHROMATIN material.Device Removal: Removal of an implanted therapeutic or prosthetic device.