Product review (1 stars): 2 defective new switches in a row
Bought 1st switch to replace one that would not regulate temperature.  Item was fulfilled by Amazon.  Installed and did not work.  Burner would not come on at all.  Removed and observed that contacts inside switch did not mate and connect like they were supposed to (this still worked on the old switch).  Ordered replacement from Amazon.  Checked replacement before installing and it looked to have the same problem.  Installed anyway to check.  Same result.  No burner operation.

Went to local appliance supply.  Observed their in stock switch and contacts operated as they were supposed to.  Same switch in same bag and same supplier name (Robertshaw).  Had to pay way more than the Amazon price and a 20 mile trip, but it works.  Local appliance supply person suggested that the Amazon switch might be a knock-off product (both switches had the same printing on them).  Seems somewhat plausible as I cannot imagine that a decent manufacturer would let any switch go out without a test for basic functionality.  Two bad switches in a row does not seem coincidental.  It would be a shame if Amazon was selling items that were sub-standard as the real thing.  I'll probably never know if the products were legit and just part of a bad batch or something else.  Sending 2nd switch back to Amazon for refund.