vlookup not returning correct reply

Hi folks, I'm having a problem that has me baffled (Obfuscated). I have a couple columns similar to this...

Column A Column B

W12x140 W12x12
W12x150 W12x12
W12x160 W12x12
W12x170 W12x14
W12x180 W12x14

There are about 100 more similar entries in this listing with varying sizes.

Column A is a size (12) and weight (140) of a piece of steel.
Column B is the size (12) and width of the corresponding weights.

I have named the the entire set of entries as "sizes"

I enter "vlookup(sizes,"W12x150",2) in cell C1 and get a result of "W12x14".

Regardless of what I put in the "vlookup" entry, I always get the very last entry as the answer.

The vlookup query above should give W12x12 as the result but I always get W12x14...or whatever the last entry is in the range.

I have looked this over until I'm blue in the face...any help?