Y Adapter for 1.75mm filament dual extruders and single nozzle

I have tried few y adapter from other posting, but never found one that works for me. I decided to make one myself.

Few things I found to make the design better.

1. inbound wider tunnel, 3mm diameter, to receive filament. To avoid hitting tunnel wall when feeding filament from PC4-M6 fittings
2. outbound 2mm diameter tunnel to feed filament. To avoid hitting PC4 or PTFE wall when feeding filament from the adapter
3. avoiding sharp curve and S-curve in the tunnel
4. It works better with