Dutton-Lainson DLX-SF Manual Swivel Trailer Jack This marine trailer jack is easy to install and swivels up locking in place for convenient towing. The unique high density plastic foot is fully articulating and strengthened with steel brackets. Easy to install, this trailer is designed to fit square tongues up to 3 x 4. The side wind cushioned handle features an ergonomic handle grip with an extra heavy screw drive to help do the heavy lifting. Dutton-Lainson offers easy to use trailer jacks to