Headwear; Helmet liners being headwear; Insulative soft headwear that aids in maintaining a user's core body temperature at an euthermic range; medical apparatus in the form of soft headwear and disposable headwear for maintaining a user's core body temperature at an euthermic range for medical use; headwear for use in medical examination and treatment; surgical caps; Medical apparel for use in medical examination and treatment, namely, insulative soft headwear; Medical apparel for use in medical examination and treatment, namely, soft insulative helmet liners being headwear that incorporates head heating or head cooling to aid in maintaining a user's core bod; thermal regulating head covers used for maintaining a user's core body temperature within an euthermic range, incorporating and supporting wearable biometric sensors for monitoring human body vital signs, remote electronic devices for monitoring body vitals