Part number NA378048 is a genuine DeWalt Output Shaft Assembly (Output Shaft SA) designed for several models of cordless chainsaws, including:
Dewalt DCM565 18v XR 30cm Brushless Cordless Chainsaw
DeWalt DCCS620B Type 3 Chainsaw
Stanley Fatmax SFMCCS630M1-GB 18V V20 30cm Chainsaw