Z-Lock(TM) 4" Set Back Manual Single Adjust Jack PlateZ-Lock Jack Plate Revolutionary Design Adds Strength and Stability. The excellence of T-H Marine&';s HI-JACKER(TM) jack plate series continues with the Z-Lock Manual Jack Plate design upgrade.Features: Z-Lock(TM) Jack Plate Design Eliminates Side Slippage Matching slotted extrusions LOCK side plates in place Strong Aircraft Grade Aluminum Full A 1/2" Material For Strength Handles All V6 and V8 Outboards up to 300 hp Easy to Adjust From Top of Jack Available in 4", 6", 8", 10" and 12" setbacks 5" of Vertical Adjustment WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.