Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:5137605.

For your BIQU B1 3D printer ... this is a print bed AC heater wire strain relief part that is modified to have a 90 degree turn, for use with my remixed IKEA Lack Table enclosure, which is also for the BIQU B1, available in two versions here:

(V1) For BIQU B1 - DIY Enclosure - Remix of Prusa IKEA Lack Enclosure - with extra doors (opening on 3 sides)

(V2) For BIQU B1 - DIY Enclosure - Remix of Prusa V2 IKEA Lack Enclosure - with extra doors (opening on 3 sides)

I recommend printing this in PETG because of the heat exposure, although PLA may work for you.

Note: It's deliberately shorter than the original part it replaces. That's to reduce the amount of clearance needed at the back of the enclosure.