Steering links are made to fit your specific rigs. If you don't have a stock setup then please give us your eye to eye length on your tie rod between the knuckles and your servo to farthest knuckle link.
Delrin (1/4") is the lightest and slides the best over rocks, logs, and other trail debris.
Brass (1/4") is sturdy and heavy and will give you a good weight up front. The tie rod is bent away both ends to clear the diffs and give the most steering.