I had four 99's I wanted to fix up to get out of the house and bought four slide plates. For some reason they fit the 66's slighty better than the 99's. On 1 or 2 I swapped plates with the 66's and the other two I had to peen the groove on the underside so they would not constantly fall off the spring when opening. Still wasn't thrilled with any of the four. I learned my lesson and stick with original used parts if possible and would be reluctant to try aftermarket foreign slide plates again. Could have been a bad batch that slipped by QC as the other overseas parts I've gotten have been OK for the price.