Universal Double Adjuster Tube Adapter 1 1/4 Inch LHT 1 1/2 Inch ID Tube (SYN3620-1214)Description Double Adjuster Tube Adapter Synergy MFG 1 1 4 inch 12 Left Hand Thread, 1 1 2 inch ID Tube. The Synergy Double Adjuster Tube Adapter is designed to eliminate the need for jam nuts that are normally used when building link suspension and steering systems. The use of the Double Adjuster allows the suspension steering link to be adjusted without removal. The Double Adjuster allows the user to fine tune the suspension steering geometry by