There are three different Remington calls them "Operating handles".
1) The original, has a depression in the bottom surface that a detent ball fits into. all gauges up to 1987 Part# F99915
2) New for the 1187, has a notch in the edge for new style detent. 1187 and later 12 gauge 1100 Part# F92034
3) Universal replacement, it has both the hole and notch and works with all gauges of the 1187 and 1100. Part# F91197
Last edited by mag410; 07/21/22. Reason: add part#'s