BERNINA L8 series #XL piping foot
Low in store inventory, may be subject to change
Piping foot for serging functions on all the BERNINA L8 series machines. Instructions included.
https://www.bernina.com/en-US/Accessories-US/Overlocker-Accessories/Presser-Feet-for-Overlocker/XL-Piping-Foot
Don't use the needle threader with this foot.