TAKE A LOOK AT ECKCRAFT.COM, HAVE A SET OF THESE ON MINE.
GREAT LOOK, BUT A LITTLE PRICEY, MAKE SURE YOU TELL THEM IT'S FOR A BIG DOG AS THE SWIVELS ARE A LOT BEEFIER TO ABSORB THE VIBRATION'S.
AS FAR AS THE ADAPTERS, I GOT TWO SETS FROM CALIFORNIA BIG DOG, HAD TO USE THE SPACERS.