Description:1. A pillow that is too high can cause excessive forward movement of the cervical spine, disrupting its normal physiological curvature, resulting in neck pain, stiffness, limited mobility, and even hunchback.2. A pillow that is too low can cause the head to tilt back excessively, affecting normal breathing and hindering blood flow back to the head.3. This product comes in size, with heights of 6cm4.Due to the fact that the pillow is shipped under vacuumcompression and received in a vacuum compressed state, itmay feel flattened when the compression bag is opened.Thisis a normal phenomenon,Simply follow the instructions in the picture below, gently tap or air dry the pillow core to restore its natural fluffiness. class="extend--iframe--to7hHIV" data-spm-anchor-id="a2g0o.detail.0.i2.1dc3KySnKySnig" data-spm-act-id="a2g0o.detail.0.i2.1dc3KySnKySnig" style="box-sizing: border-box; -webkit-tap-highlight-color: transparent; outline: 0px; margin: 0px; padding: 0px; height: 19125.2px; position: absolute; top: 0px; visibility: hidden; z-index: -1;">