Pentax offers two DA zoom lenses with a 50-200mm range:
smc PENTAX DA 50-200mm F4-5.6 ED WR
smc PENTAX DA 50-200mm F4-5.6 ED
The only obvious difference I see between them is that one is weather sealed and the other is not. However, they each list for $249.95 on the Pentax web store. This leads me to suspect that there must be other differences to make the non-weather sealed lens competitive at that price. What am I missing?