This AQUECOIL™ HWC-2030-A-3 duct mounted coil has a 20" x 30" finned surface area and is 3 rows deep.  Made in the USA.

The AQUECOIL Hot Water Coil A-Series works in conjunction with any source of hot water (which can supply enough BTUs to meet your heating load), such as a Conventional Water Heater, a Tankless Water Heater, or Boiler, and an air distribution system. AQUECOIL Hot Water Coils may be mounted in either the supply or the return side of the duct system, in either vertical or horizontal orientation. The addition of an external air vent is recommended to assure complete air purging.

Quick Specifications: Galvanized steel frame with 1" flange using 18 gauge brackets and 20 gauge sides. Copper waterways using 1/2" O.D. seamless tubes with .017" walls. 500 PSI maximum operating pressure, 2500 PSI ultimate pressure.  Aluminum fins are .0045" thick and tubes are expanded into fins for permanent surface bond and maximum heat transfer.

Specification Sheet: http://aquecoil.com/specs/hwcspecs/files/AQUECOIL_HWC_A-Series.pdf