TM 1-1510-218-10 3-26 Table 3-7.  Runway Surface (Continued) DISPLAY EXPLANATION HRD Hard  surface  (includes  asphalt, concrete, pavement, sealed, tarmac, brick, and bitumen) ICE Ice MAT Steel matting SHL Shale SND Sand SNW Snow TRF Turf (4)   Airport 4 Page.  The APT 4 page is used to display communication frequencies.  Refer to Figure 3-23. (a)  Airport Identifier.  An arrow precedes the identifier if it is the active waypoint. (b)  Frequencies.    Refer  to  Table  3-8 for frequency abbreviations and their explanations. KORL ATIS*127.25 CLR *118.05 GRND*121.40 TWR *118.70 CTAF*118.70 APT+4 Figure 3-23.  APT 4 Page Table 3-8.  Frequency Abbreviations   DISPLAY EXPLANATION AAS Aeronautical advisory service AFIS Aerodrome flight information service APR Approach control ARVL Arrival ATF Aerodrome traffic frequency Table 3-8.  Frequency Abbreviations   (Continued) DISPLAY EXPLANATION ATIS Automatic     terminal     information service AWOS Automatic weather observing station CL B Class B (VFR frequency) CL C Class C (VFR frequency) CLR Clearance delivery CTA Control area (VFR frequency) CTAF Common traffic advisory frequency CTR Center  (when  center  is  used  for approach/departure control) DEP Departure control DIR Director (approach control/radar) GRND Ground control MF Mandatory frequency MCOM Multicom PCL Pilot controlled lighting PTAX Pre-taxi clearance RAMP Ramp/taxi control RDO Radio RDR Radar only frequency TMA Terminal area (VFR frequency) TRSA Terminal radar service area (VFR frequency) TWR Tower UNIC Unicom In  addition  to  the  standard  VHF  frequencies, HF frequencies   are   shown   at   airports   that   utilize   HF communications   in   the   2000   kHz   to   30,000   kHz frequency     band.          Airports     that     have     numerous communication  frequencies  will  have  multiple  APT  4 pages   indicated   by   APT+4.      Refer   to   Figure   3-24.   Part-time operation is indicated with an asterisk to the left of the frequency. Frequencies associated with CL B, CL C, TRSA, CTA, or TMA are VFR frequencies.  Airports that have one of these categories of frequencies also have APR and DEP which are IFR frequencies.  Where required, APR,   DEP,   CL   B,   CL   C,   TRSA,   CTA,   and   TMA frequencies  are  sectorized.    The  format  for  showing