The most common used materials are BCY #23 & BCY#24. It’s mostly personal preference which determines which to use, and the following characteristics are considered:
BCY #23 D Braid Loop Rope
- 1.6mm diameter
- Relatively softer
- Braided Spectra
- Not easy to burn
- Very durable
BCY #24 Loop Rope
- 2.0mm diameter
- Relatively stiffer
- Braided Polyester
- Easy to burn
There are plenty of resources on YouTube and the internet which shows how to tie a D-loop.