This insert is meant to fit the Gen 3 3/8 M12 Impact Driver but would most likely work on later models. The design is not perfect but works well and welcomes improvement from community. The sockets I used for the insert were from amazon along with the extensions, sparkplug socket and 1/4 impact adapters. links will be provided below. The filament used was PETG, I found a color that matched the packout red fairly well, link for that will be provided.

Red Filament: https://www.amazon.com/dp/B0DPSHHHYR?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 3/8 Impact socket set: https://www.amazon.com/dp/B0B2R4Q9GX?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 1/4 Drive Adapters: https://www.amazon.com/dp/B07MH3MGGF?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 5/8 Spark Plug socket: https://www.amazon.com/dp/B07QG4HD1K?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 Impact extensions kit: https://www.amazon.com/dp/B0D6VMHH2K?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 Torx bit socket set: https://www.amazon.com/dp/B07M9ZF35W?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 Hex bit socket set: https://www.amazon.com/dp/B07MR771P4?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1