+.B --rsyncable
+While compressing, synchronize the output occasionally based on the input.
+This increases size by less than 1 percent most cases, but means that the
+.BR rsync (1)
+program can take advantage of similarities in the uncompressed input
+when syncronizing two files compressed with this flag.
+.I gunzip
+cannot tell the difference between a compressed file created with this option,
+and one created without it.
+.TP