The SA2216 is a 2×2 2.4 GHz external antenna with 2 N-type connectors.
The SA5219 is a 2×2 5 GHz antenna with 2 N-type connectors. The
SA2216 and SA5219 have similar casing and form-factor.

The ENH710EXT is a dual-band 2×2:2 802.11n outdoor wireless access
point with two (2) removable 2.4 GHz antennas and two (2) removable 5
GHz antennas.

Only one (1) SA2216 is needed to replace the two (2) 2.4 GHz antennas
and one (1) SA5219 to replace the two (2) 5 GHz antennas. 

Figure 1: ENH710EXT

Figure 2: SA5219/SA2216