SPIN STRAPS. Use With A Shoulder Harness To Help Maximize Leverage When Fighting Bigger Fish With Spinning Tackle. The AFTCO Spin-Strap,when used in conjunction with a shoulder harness, allows for increased leverage when fighting bigger gamefish with spinning tackle. The strap first wraps around the rod fore-grip, and the D-rings (one slips through strap`s slot) connect to each of the harness clips. Works perfectly with our MaxForce II Shoulder Harness.