Product review (4 stars): Instruction sheet pretty good. Pricey at $80 - prob
Fit in as a replacement OK.  Need 2 different size wrenches - 1 for the compression nut, 1 to hold the body.  Instruction sheet pretty good.  Pricey at $80 - prob. didn't cost over $25 to make, but no choice without replacing entire unit.  It's the only real 'operating' piece of the unit anyway.