Good chance it's pot metal/zinc if it's not brass. It seems like an insert that could go into a hole cast or drilled in metal or plastic. Not in wood due to the small size and number of the ridges. Something metal probably goes into the large end, shaped like the hole. On the top side is a sheetmetal spring (maybe stainless) that applies pressure in a slot to hold the piece put about 1" into the end hole. Maybe part of a tool handle? The hole is not centered so probably not a screwdriver. Maybe hardware related.