Product review (2 stars): LG5231JA2006A does NOT filter all that LG5231JA2006B does!
LG5231JA2006A only meets ANSI/NSF Standard 42, but LG5231JA2006B meets 42 & 53.  DO NOT BUY LG5231JA2006A thinking you are getting the same filtration as LG5231JA2006B.  The description is wrong on this page saying that it removes "96.7% of Mercury, 99.31% of Lead, 95.9% of Atrazine, 96.3% of Benzene, 93.06% of 2,4-D, 99.09% of Lindane, 99.99% of Cysts, 99.3% of Turbidity, 99.9% of Particulates (Class I), 97.6% of Chlorine Taste & Odor".  It only removes "93.2% of Particulates (Class I), 97.4% of Chlorine Taste & Odor".