The author remixed this model.
This version is 8mm shorter than the original, so it will work for 28mm deep fans replacing 56mm ones. Fans that shoud work are e.G.
However, any 28mm-fan should give you an enormous amount of more pressure than 20mm fans, even the S4028-6K ones…
By pure coincidence, 2 of these adapters back-to-back and a pair of cableties work excellently as constrained cable-tunnel in supermicro-cases (sc116 in my case, see pictures).