Overview
The 40509 is a non-insulated wire splice connector from TE Connectivity, rated for 3300-9000 CMA copper wire. Termination is by crimp; the ridged barrel provides mechanical grip on the conductor.
How it compares
The 40509 is non-insulated and covers 3300-9000 CMA, while the 53915-2 is fully insulated and covers 10-22 AWG — select the 40509 for bare-splice applications requiring the higher CMA range.