McKesson Instant Cold Pack, 6 x 9 Inch, 1 Case of 24 Barriers and metric scale 149 and metric scale s AFD technology provides enhanced acoustic response: light pressure for low bell type frequency firm pressure for high diaphragm type frequency Extra large bell (1 3 8 diameter) for unsurpassed low frequency response Ultra sensitive diaphragm (1 3 4 diameter) for greater amplification and crisper high frequency response Non chill bell and diaphragm retaining rims for patient comfort Clinician headset boasts reinforcing yoke molded into flexible 22 PVC tubing and stainless steel binaurals fixed at 15ß angle for greater comfort Tubing is soft flexible and made without phthalates Adsoft The easy to apply McKesson instant cold compress provides quick relief of mild pain and swelling It's suitable for dealing with minor athletic injuries