The Andrew MT-197 single-pipe support arm with mounting pipe is for use with ring mounts and a cellular pipe frame for mounting up to four (4) antennas per sector. This hot-dipped galvanized steel pipe support arm holds the 4 1/2 in OD, 18 in long mounting pipe 36 in from monopole. Secure your antenna to the mounting pipe (included).brbrThe Andrew single standoff support pipe with mounting pipe includes U-bolts for 2 3/8 in OD pipes. Cellular pipe frame and work platform are sold separately.