R134a condensers have more fins/inch than R12 condensers and their fin diameters are smaller.( 6mm)

TUBE and FIN - Oldest industry standard, 3/8-inch diameter round tube condenser. Ok, for R12 but not recommended for R134a. This type of condenser is flushable.

6 mm PICCOLO multi-flow: smaller, lightweight and more efficient than 3/8-inch tube and fin and serpentine. Used in many domestic OE applications. This type of condenser is flushable.

SERPENTINE: All aluminum, more efficient than tube and fin, used on smaller imports where space is limited. This type of condenser is not easily flushed, replacement is recommended.

PARALLEL FLOW: all aluminum, this efficient design breaks up flow into tiny streams that give up heat more rapidly. This type of condenser is not flushable, replacement only!

PARALLEL FLOW with SUB Condenser. Oval tube multi-flow and sub-condenser stacked up. Refrigerant flows through the multi-flow into the drier (called a modulator) then continues as a liquid into the sub-condenser. This type of condenser is not flushable, replacement only!