Hi - The right start and one step ahead sell them, online too!, but they are pricy. What I did was purchase a child size fanny pack, fisher price makes a cute one as does coleman kids. I happened to find a really cute one at Animal Kingdom. Then I just bought the regular harness they sell at babies r us and used the strap around the fanny pack instead of on the harness. Clear as mud? I also used it on belt loops or overalls if dd wasn't wearing the fanny pack.
FWIW we always used the harness as a" back up" and held hands with dd never "walked her" with the holder. I used it as a way to teach her to hold hands but if the impulse struck and she let go to see something that caught her eye - I had that back up. My oldest never really needed it but my younger daughter was very impulsive at the toddler age.
TJ