Depends if you want a noose or comfort strap. I use a noose extender (FastSize) and I’ve never tried the comfort strap because you can’t stretch as far. The Jes comes with a comfort strap and headpiece with slots, but they still sell silicone bands and headpieces with holes.
Most extenders are similar, but if I were you I’d look for an extender that has a range of elongation bar sizes. The FastSize had 4 different size elongation bars (L, M, S, & Micro). The small micro bars are 1/8 inch, which allow you to add length more often and slowly increase the length of the extender. Most extenders don’t have anything this small
Smallest Elongation Bars:
X4Labs = 1/3”
EuroExtender/SizeGenetics/Jes = 1/2”
AndroPenis = 1/8”