Browse our Shift Lock replacement gooseneck stem & couplers, inner tube goose stems with gooseneck couplers. Our patented shift lock gooseneck couplers are available with for round & square tube gooseneck stem. Available for 2-5/16 & 3 inch gooseneck balls & king pin. Offset step options too. Great for flat beds, horse, cargo, livestock, utility, flatbed, car, and more. 9" offset extension couplers for short bed trucks. 30,000 to 40,000 lbs GTW for 2-5/16" & 3" Gooseneck Balls.